Sperm Protamine mRNA Ratio and DNA Fragmentation Index Represent Reliable Clinical Biomarkers for Men with Varicocele after Microsurgical Varicocele Ligation

Effects of Varicocele Repair on Sperm DNA Fragmentation and Seminal Malondialdehyde Levels in Infertile Men with Clinical Varicocele: A Systematic Review and Meta-Analysis

PURPOSE

Varicoceles can be a source of elevated seminal oxidative stress (OS) and sperm DNA fragmentation (SDF). However, it remains unclear whether varicocele repair (VR) could reduce these parameters. This systematic review and meta-analysis (SRMA) aims to investigate the impact of VR on SDF and seminal malondialdehyde (MDA).

MATERIALS AND METHODS

A literature search was performed in Scopus, PubMed, Ovid, Embase, and Cochrane databases. This SRMA included randomized controlled trials and observational studies reporting the pre- and postoperative levels of SDF and seminal OS in infertile men with clinical varicocele that underwent VR. Subgroup analyses included techniques of VR and SDF testing. The effect size was expressed as standardized mean difference (SMD).

RESULTS

Out of 1,632 abstracts assessed for eligibility, 29 studies with 1,491 infertile men were included. The analysis showed a significant reduction in SDF after VR, compared to preoperative values (SMD -1.125, 95% confidence interval [CI] -1.410, -0.840; p<0.0001) with high inter-study heterogeneity (I²=90.965%). Reduction in SDF was evident with microsurgical technique and non-microsurgical inguinal approaches (SMD -1.014, 95% CI -1.263, -0.765; p<0.0001, and SMD -1.495, 95% CI -2.116, -0.873; p<0.0001), respectively. Reduction in SDF was significant irrespective of testing was done by sperm chromatin dispersion (SMD -2.197, 95% CI -3.187, -1.207; p<0.0001), sperm chromatin structure assay (SMD -0.857, 95% CI -1.156, -0.559; p<0.0001) or TUNEL (SMD -1.599, 95% CI -2.478, -0.719; p<0.0001). A significant decrease in seminal MDA levels was observed following VR (SMD -2.450, 95% CI -3.903 to -0.997, p=0.001) with high inter-study heterogeneity (I²=93.7%).

CONCLUSIONS

Using pre- and post-intervention data, this SRMA indicates a significant reduction in SDF and seminal MDA levels in infertile men with clinical varicocele treated with VR. These findings may have important implications for the future management of this selected group of infertile patients.

The Evolving Landscape of Male Varicocele Pathophysiology in the Era of Multi-Omics: A Narrative Review of the Current Literature

Male-factor infertility is implicated in over half of the millions of cases of infertility worldwide, and varicoceles are the most common correctable cause of male-factor infertility. The pathophysiologic mechanism for varicoceles is complex and next-generation technologies offer promising insights into the molecular underpinnings of this condition. In this narrative review, we highlight historical and contemporary paradigms associated with varicoceles, with an emphasis on the biological underpinnings of this disease. Specifically, we review the literature describing the underlying causes of varicoceles, discuss the molecular and cellular mechanisms causing pathological changes in some (but not all) men, and highlight key articles regarding the next-generation analyses (e.g., transcriptome, epigenome, proteome, and microbiome) being applied to better understand the condition and its treatment. These data demonstrate an ongoing evolution of the knowledge of varicoceles and the potential for improved personalized care in the future for men with this condition.

[Varicocele and male infertility]

BACKGROUND

Varicocele is the most common correctable cause of male infertility. It was the subject of recent Association française d'urologie (AFU) Comité d'andrologie et de médecine sexuelle (CAMS) recommendations. Since then, the literature has provided additional information. This review will comprehensively reassess current indications for the treatment of varicocele, and revisit contemporary issues in the light of current advances.

METHODS

Update of the literature search carried out as part of the CAMS recommendations for the period between 2020 and 2023.

RESULTS

Microsurgical sub-inguinal varicocelectomy remains the surgical treatment of choice for infertile men with clinical varicocele and abnormal sperm parameters. It offers recurrence rates of less than 4%. It significantly improves both natural and in vitro fertilization live birth and pregnancy rates, as well as sperm count, total and progressive motility, morphology and DNA fragmentation rates. All in all, it modifies the MPA strategy in around one in two cases. Varicocele grade and bilaterality are predictive of improved sperm parameters and pregnancy rate. Treatment of subclinical varicocele is not recommended. Complications are rare, notably hydroceles (0.5%), unilateral testicular atrophy due to arterial damage (1/1000), hematomas, delayed healing and postoperative pain. Retrograde embolization is an alternative to surgery.

CONCLUSION

Whenever possible, the urologist should present and discuss treatment options for varicocele with the MPA team and the patient, taking a personalized approach.

Resveratrol ameliorates spermatogenesis by increasing protamine 1, 2 and HSPA2 expression in experimental varicocele rat model

OBJECTIVES

Varicocele is a common cause of male infertility associated with an elevated testicular temperature that induces apoptosis, spermatogenesis dysfunction, and affects sperm parameters. In this study, we investigate the probable therapeutic effects of resveratrol (RES), a natural phytoalexin, against varicocele.

MATERIALS AND METHODS

In this study, 48 male Wistar rats randomly divided into 8 groups: normal, sham, normal+RES (20 and 50mg/kg), varicocele, varicocele+ethanol and varicocele+RES (20 and 50mg/kg). Incomplete closure of the left renal vein was used for varicocele induction and two months later, RES was administrated orally for 60 days. Then, sperm parameters, DNA fragmentations, chromatin density, and testis histopathology were analyzed. In addition, HSPA2, protamine 1, and 2 expression levels were evaluated using real-time PCR.

RESULTS

According to our results, resveratrol treatment improved sperm parameters, testis histopathology, DNA fragmentation, and chromatin maturation which damaged follow varicocele (p≤0.05). Also, it increased HSPA2, protamine 1, and 2 expression levels significantly in both doses (p≤0.05).

CONCLUSION

Resveratrol potentially attenuates varicocele-induced spermatogenic impairments by its antioxidant features and regulates spermatogenic gene expression undergoing DNA fragmentation, so leads histopathological properties of tissues to physiological parameters.

Varicocele associated male infertility: cellular and molecular perspectives of pathophysiology

BACKGROUND

Varicocele is a common risk factor associated with reduced male fertility potential. The current understanding of varicocele pathophysiology does not completely explain the clinical manifestation of infertility. The present treatment options such as antioxidant supplementation and varicocelectomy only helps ∼35% of men to achieve spontaneous pregnancy.

OBJECTIVE

This review aims to summarize the available knowledge on cellular and molecular alterations implicated to varicocele associated male infertility and also highlights the new knowledge generated by 'Omics' technologies.

MATERIALS AND METHODS

PubMed, MEDLINE, Cochrane and Google Scholar databases are searched using different combinations of keywords (varicocele, infertile/fertile men with varicocele, cellular changes, molecular mechanisms, proteome, epigenome, transcriptome and metabolome). A total of 229 relevant human and animal studies published till 2021 were included in this review.

RESULTS

Current understanding advocates oxidative stress (OS) as a major contributory factor to the varicocele associated male infertility. Excessive OS causes alteration in testicular microenvironment and sperm DNA fragmentation which further contributes to infertility. Molecular and omics studies have identified several promising biomarkers such as AAMP, SPINT1, MKI67 (genetic markers), sperm quality and function related protein markers, global sperm DNA methylation level (epigenetic marker), Hspa2, Protamine, Gadd7, Dynlt1 and Beclin1 (mRNA markers), PRDX2, HSPA, APOA2, YKL40 (seminal protein markers), total choline and PHGDH (metabolic markers).

DISCUSSION

Mature spermatozoa harbours a plethora of molecular information in form of proteome, epigenome and transcriptome; which could provide very important clues regarding pathophysiology of varicocele associated infertility. Recent molecular and omics studies in infertile men with varicocele have identified several promising biomarkers. Upon further validation with larger and well-defined studies, some of these biomarkers could aid in varicocele management.

CONCLUSION

The present evidences suggest inclusion of OS and sperm DNA fragmentation tests could be useful to the diagnostic workup for men with varicocele. Furthermore, including precise molecular markers may assist in diagnostics and prognostics of varicocele associated male infertility. This article is protected by copyright. All rights reserved.

The Association of Certain Seminal Phthalate Metabolites on Spermatozoa Apoptosis: An Exploratory Mediation Analysis via Sperm Protamine

Earlier studies have suggested that exposure to phthalates (PAEs) may induce spermatozoa apoptosis. Sperm protamine as a molecular biomarker during spermatozoa apoptotic processes may mediate the association between PAE exposure and spermatozoa apoptosis. This study aimed to explore whether sperm protamine mediates the association of PAE exposure with spermatozoa apoptosis. We determined sperm protamine levels, 8 PAE metabolite concentrations in seminal plasma, and 3 spermatozoa apoptosis parameters among 111 men from an infertility clinic. The associations of PAEs as individual chemicals and mixtures with sperm protamine were determined. The mediating roles of protamine in the associations between PAEs and spermatozoa apoptosis parameters were examined by mediation analysis. After adjusting for confounders, we observed positive correlations between seminal plasma concentrations of mono(2-ethylhexyl) phthalate (MEHP) and sperm protamine-1 and protamine ratio. Estimates comparing highest vs. lowest quartiles of MEHP concentration were 4.65% (95% CI: 1.47%, 7.82%) for protamine-1 and 25.86% (95% CI: 3.05%, 53.73%) for protamine ratio. The quantile g-computation models showed that the adjusted protamine-1 per quartile increase in PAE mixture was 9.42% (95% CI: 1.00, 20.92) with MEHP being the major contributor. Although the joint association between PAE mixture and protamine ratio was negligible, MEHP was still identified as the main contributor. Furthermore, we found that protamine-2 and protamine ratio levels in the highest quartiles exhibited a decrease of 43.45% (95% CI: 60.54%, -19.75%) and an increase of 122.55% (95% CI: 60.00%, 209.57%) in Annexin V⁺/PI^- spermatozoa relative to the lowest quartiles, respectively. Mediation analysis revealed that protamine ratio significantly mediated 55.6% of the association between MEHP and Annexin V⁺/PI^- spermatozoa elevation (5.13%; 95% CI: 0.04%, 10.52%). Our findings provided evidence that human exposure to PAEs was associated with increased protamine levels which may mediate the process of spermatozoa apoptosis.

Chronic Prostatitis/Chronic Pelvic Pain Syndrome Leads to Impaired Semen Parameters, Increased Sperm DNA Fragmentation and Unfavorable Changes of Sperm Protamine mRNA Ratio

BACKGROUND

Chronic Prostatitis/Chronic Pelvic Pain Syndrome (CP/CPPS) is a frequent disease affecting men of every age and accounting for a great number of consultations at urology departments. Previous studies suggested a negative impact of CP/CPPS on fertility. As increasing attention has been attributed to additional aspects, such as sperm DNA integrity and sperm protein alterations, besides the WHO standard semen analysis when assessing male fertility, in this prospective study, we aimed to further characterize the fertility status in CP/CPPS patients with a focus on these parameters.

METHODS

Sperm DNA fragmentation measured by sperm chromatin structure assay (SCSA) and protamine 1 to protamine 2 mRNA ratio assessed by RT-qPCR were analyzed along with conventional ejaculate parameters and inflammatory markers in 41 CP/CPPS patients and 22 healthy volunteers.

RESULTS

We found significant differences between the groups concerning multiple conventional ejaculate parameters. A significant increase in sperm DNA fragmentation was shown in CP/CPPS patients with association to other sperm parameters. The majority of CP/CPPS patients exhibited protamine mRNA ratios out of the range of regular fertility.

CONCLUSIONS

This is a pioneering study with a strong practical orientation revealing that CP/CPPS leads to increased sperm DNA damage and changes in sperm protamine levels, emphasizing an unfavorable impact of CP/CPPS on fertility.

Effect of varicocelectomy on sperm deoxyribonucleic acid fragmentation rates in infertile men with clinical varicocele: a systematic review and meta-analysis

OBJECTIVE

To evaluate the effect of varicocelectomy on sperm deoxyribonucleic acid fragmentation (SDF) rates in infertile men with clinical varicocele.

DESIGN

Systematic review and meta-analysis.

SETTING

Not applicable.

PATIENT(S)

Infertile men with clinical varicocele subjected to varicocelectomy.

INTERVENTION(S)

Systematic search using PubMed/Medline, EMBASE, Cochrane's central database, Scielo, and Google Scholar to identify relevant studies published from inception until January 2021. We included studies comparing SDF rates before and after varicocelectomy in infertile men with clinical varicocele.

MAIN OUTCOME MEASURE(S)

The primary outcome was the difference between the SDF rates before and after varicocelectomy. A meta-analysis of weighted data using random-effects models was performed. Results were reported as weighted mean differences (WMD) with 95% confidence intervals (CIs). Subgroup analyses were performed on the basis of the SDF assay, varicocelectomy technique, preoperative SDF levels, varicocele grade, follow-up time, and study design.

RESULT(S)

Nineteen studies involving 1,070 patients provided SDF data. Varicocelectomy was associated with reduced postoperative SDF rates (WMD -7.23%; 95% CI: -8.86 to -5.59; I² = 91%). The treatment effect size was moderate (Cohen's d = 0.68; 95% CI: 0.77 to 0.60). The pooled results were consistent for studies using sperm chromatin structure assay, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling, sperm chromatin dispersion test, and microsurgical varicocele repair. Subgroup analyses showed that the treatment effect was more pronounced in men with elevated vs. normal preoperative SDF levels, but the impact of varicocele grade remained equivocal. Meta-regression analysis demonstrated that SDF decreased after varicocelectomy as a function of preoperative SDF levels (coefficient: 0.23; 95% CI: 0.07 to 0.39).

CONCLUSION(S)

We concluded that pooled results from studies including infertile men with clinical varicocele indicated that varicocelectomy reduced the SDF rates. The treatment effect was greater in men with elevated (vs. normal) preoperative SDF levels. Further research is required to determine the full clinical implications of SDF reduction for these men.

The impact of varicocelectomy on sperm DNA fragmentation and pregnancy rate in subfertile men with normal semen parameters: A pilot study

Objective: To evaluate the outcome of microscopic subinguinal varicocelectomy on sperm DNA fragmentation (SDF) and pregnancy rate in men with normal semen parameters.

Patients and methods: A pilot study that included male patients with a minimum of a 1-year history of male subfertility, normal semen parameters, a high percentage of SDF, and clinically palpable varicoceles. Microscopic subinguinal varicocelectomy was carried out for 45 patients (study group), while 40 patients had no intervention (control group). Semen analysis and SDF were measured before and at 6 months after the varicocelectomy. The pregnancy rate was assessed at the 6- and 12-month follow-ups.

Results: Between July 2014 and January 2019, 85 subfertile men were included in the study and completed 12 months of follow-up. The two groups were comparable in terms of their age, body mass index, infertility duration, infertility type, varicoceles laterality, and varicoceles grade (P values = 0.84, 0.34. 0.35, 1, 0.39, and 0.46, respectively). At 6 months after varicocelectomy, the mean SDF was reduced in both groups, and this reduction was statistically higher in the varicocelectomy group (P < 0.001). After 1-year, spontaneous pregnancy was achieved in 62% of the patients in the varicocelectomy group compared to 30% in the control group (P = 0.009).

Conclusion: Varicocelectomy has a positive impact on SDF and spontaneous pregnancy in infertile men with clinically palpable varicoceles and normal semen parameters.

Abbreviations: BMI: body mass index; DFI: DNA fragmentation Index; SDF: sperm DNA fragmentation

Protamine 1/Protamine 2 mRNA ratio in nonobstructive azoospermic patients

Altered protamine 1 (PRM1)/ protamine 2 (PRM2) mRNA ratio in testicular biopsy samples correlates with sperm quality and its fertilising ability. This study is planned to assess PRM1/ PRM2 mRNA ratio in subgroups of azoospermia to suggest a more reliable and accurate marker for assessing sperm quality in nonobstructive azoospermia (NOA). A cross-sectional study was done on testicular biopsy samples, taken from 106 azoospermic patients. Samples were histologically classified into subgroups: 36 obstructive azoospermia (OA), and two groups of NOA: 41 round spermatid maturation arrest (SMA) and 29 Sertoli cell-only syndrome (SCOS). OA samples showed histologically normal spermatogenesis and serve as a positive control. mRNA expression of jumonji domain-containing 1A (JMJD1A), PRM1, PRM2 and transition nuclear proteins (TNP1, TNP2) genes was determined, by RT-qPCR. Significantly lower expression of JMJD1A (p < .001), PRM1 (p = .0265) and PRM2 (p = .0032) has been seen in the SCOS group of NOA. We found significant (p < .001) increase in PRM1/PRM2 mRNA ratio in testicular biopsy samples of SCOS group of NOA patients and significant negative correlation of PRM1/PRM2 mRNA ratio with JMJD1A. Hence, PRM1/PRM2 mRNA ratio may represent a more reliable and accurate marker to assess sperm quality in NOA in addition to standard semen parameters.

In Silico Sperm Proteome Analysis to Investigate DNA Repair Mechanisms in Varicocele Patients

Varicocele, a condition associated with increased oxidative stress, negatively affects sperm DNA integrity and reduces pregnancy rates. However, the molecular mechanisms related to DNA integrity, damage, and repair in varicocele patients remain unclear. This study aimed to determine the role of DNA repair molecular mechanisms in varicocele-related infertility by combining an in silico proteomics approach with wet-laboratory techniques. Proteomics results previously generated from varicocele patients (n=50) and fertile controls (n=10) attending our Andrology Center were reanalyzed using bioinformatics tools, including the WEB-based Gene SeT AnaLysis Toolkit, Open Target Platform, and Ingenuity Pathway Analysis (IPA), to identify differentially expressed proteins (DEPs) involved in DNA repair. Subsequently, selected DEPs in spermatozoa were validated using western blotting in varicocele (n = 13) and fertile control (n = 5) samples. We identified 99 DEPs mainly involved in male reproductive system disease (n=66) and male infertility (n=47). IPA analysis identified five proteins [fatty acid synthase (FASN), myeloperoxidase (MPO), mitochondrial aconitate hydratase (ACO2), nucleoporin 93 (NUP93), and 26S proteasome non-ATPase regulatory subunit 14 (PSMD14)] associated with DNA repair deficiency, which showed altered expression in varicocele (P <0.03). We validated ACO2 downregulation (fold change=0.37, change%=-62.7%, P=0.0001) and FASN overexpression (fold change = 4.04, change %= 303.7%, P = 0.014) in men with varicocele compared to controls. This study combined a unique in silico approach with an in vitro validation of the molecular mechanisms that may be responsible for varicocele-associated infertility. We identified ACO2 and FASN as possible proteins involved in DNA repair, whose altered expression may contribute to DNA damage in varicocele pathophysiology.

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.

Best laboratory practices and therapeutic interventions to reduce sperm DNA damage

Conventional semen analysis is considered the cornerstone investigation for infertile men. Nonetheless, this routine test does not provide information on important sperm functions like sperm DNA fragmentation (SDF). Abnormalities of human spermatozoal nucleus and chromatin have a detrimental impact on both natural and assisted reproductive outcomes. In vivo, SDF results from abnormalities in chromatin compaction, abortive apoptosis and oxidative stress, while in vitro, a number of factors may be implicated. Various SDF testing methods are available, and the most commonly utilised assays include terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL), sperm chromatin dispersion (SCD) test, sperm chromatin structure assay (SCSA) and Comet assay. SDF testing has shown beneficial effects on treatment decision-making; however, its routine use in the initial evaluation of infertile men is still not recommended. One of the treatment options to reduce sperm DNA damage is the use of antioxidants. Despite the documented improvement in semen parameters and sperm DNA integrity following antioxidant therapy, no definitive recommendation is reached due to lack of large, well-designed, randomised, placebo-controlled trials assessing their exact role in male factor infertility. The objectives of this review article are to illustrate the aetiologies of SDF, to describe the effects of SDF on male factor fertility, to explore the common techniques utilised in SDF testing, to review the clinical indications for SDF testing and to review the effect of antioxidant therapy as a method to alleviate SDF.

Comparison of ART outcomes in men with altered mRNA protamine 1/protamine 2 ratio undergoing intracytoplasmic sperm injection with ejaculated and testicular spermatozoa

Assisted reproductive technologies involving the use of spermatozoa and eggs for in vitro fertilization (IVF) have come as the solution for many infertile couples to become parents. However, in some cases, the use of ejaculated spermatozoa delivers poor IVF performance. Some studies have suggested the use of testicular spermatozoa in severe male infertility cases, but no guidelines regarding their utilization are currently available. In the present study, we found the mRNA protamine 1/protamine 2 (P1/P2) ratio to be a valuable biomarker of poor sperm function that could be used as a diagnostic key for the identification of cases that would benefit from the use of testicular spermatozoa. A total of 23 couples undergoing egg donation cycles with at least one previous cycle failure were studied. All couples underwent two consecutive intracytoplasmic sperm injection (ICSI) cycles with either ejaculated or testicular spermatozoa (TESA). The sperm mRNA P1/P2 ratio, fertilization rate, blastocyst rate, and pregnancy and live birth rate were compared. Results showed improved ICSI and clinical outcomes in cycles with testicular spermatozoa in men with altered mRNA P1/P2 ratios. TESA cycles presented significantly higher rates of fertilization (mean ± standard deviation: 76.1% ± 15.1% vs 65.5% ± 18.8%), blastocyst formation (55.0% ± 20.3% vs 30.8% ± 23.8%), and good morphological quality blastocyst (28.9% ± 22.9% vs 13.5% ± 17.9%) and also improvements on pregnancy (60.9% vs 0%) and healthy birth rates (56.5% vs 0%) than EJACULATE cycles. The results described here suggest that in patients with previous IVF/ICSI failures and aberrant mRNA protamine ratios, the use of testicular spermatozoa may be a good alternative to improve clinical outcomes.

Sperm microRNA pairs: new perspectives in the search for male fertility biomarkers

OBJECTIVE

To identify candidates of fertility biomarkers among pairs of human sperm microRNAs.

DESIGN

Expression data of 736 sperm microRNAs from fertile and infertile individuals characterized in previous published studies by means of TaqMan quantitative polymerase chain reaction (PCR) were reexamined. A set of microRNA pairs with the best biomarker potential were selected and validated by means of quantitative real-time (qRT) PCR in an independent cohort.

SETTING

University laboratory.

PATIENT(S)

Semen samples were obtained from fertile (n = 10) and infertile (asthenozoospermia, n = 10; teratozoospermia, n = 10; oligozoospermia, n = 10; unexplained male infertility [UMI], n = 8) individuals. The validation cohort included 9 fertile donors and 14 infertile patients with different seminal alterations.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Spearman test was used to select microRNA pairs with a correlated expression in fertile individuals and a noncorrelated expression in each infertile group. The biomarker potential of these pairs was determined with the use of receiver operating characteristic curves. The differential relative expression of each pair in fertile and infertile populations was verified (Mann-Whitney test). Those pairs with best results were validated by qRT-PCR.

RESULT(S)

Forty-eight pairs showed significant correlations in the fertile group. The pairs that were uncorrelated in the infertile populations and displayed the best biomarker potential were hsa-miR-942-5p/hsa-miR-1208 (asthenozoospermia), hsa-miR-296-5p/hsa-miR-328-3p (teratozoospermia), hsa-miR-139-5p/hsa-miR-1260a (oligozoospermia), and hsa-miR-34b-3p/hsa-miR-93-3p (UMI). The hsa-miR-942-5p/hsa-miR-1208 pair showed the greatest potential for detecting seminal alterations in the validation cohort (85.71% true positives).

CONCLUSION(S)

The pairs hsa-miR-942-5p/hsa-miR-1208 and hsa-miR-34b-3p/hsa-miR-93-3p have the potential to become new molecular biomarkers that could help to diagnose male infertility, especially in cases of UMI or when seminal parameters are close to the threshold values.

Interventions to Prevent Sperm DNA Damage Effects on Reproduction

Excessive oxidation and antioxidant imbalance resulting from several conditions may cause sperm DNA damage, which, in turn, affect male fertility, both natural and assisted. Sperm DNA damage transferred to the embryo might also affect the health of offspring. Several conditions associated with excessive oxidative stress are modifiable by the use of specific treatments, lifestyle changes, and averting exposure to environmental/occupational toxicants. Here, we discuss the strategies to reduce sperm DNA damage with a focus on clinical and surgical interventions.

Extended indications for varicocelectomy

The relationship between varicoceles and subfertility is well-established, but recent evidence suggests that varicoceles may cause global testicular dysfunction. This has led to exploration into expanding the indications for varicocelectomy. This review examines the literature regarding varix ligation as a treatment for non-obstructive azoospermia, elevated DNA fragmentation, and hypogonadism.

Indications and outcomes of varicocele repair

Varicoceles exert deleterious effect on testicular function. The condition has been associated with male infertility, testicular hypotrophy and pain. These comprises the common indications for varicocele repair currently. Significant improvement in semen parameters and pregnancy outcomes had been suggested by reports decades ago. However, selection of the best candidates remains an issue since not all patients respond positively to treatment. Consensus has been reached in recent decade after the publication of a series of meta-analyses. Significant improvement in pregnancy outcomes were reported in patients with clinical varicocele and abnormal semen parameters. Varicocelectomy in adolescents with testicular hypotrophy was supported by the positive implication on catch-up growth and semen parameters. However, little is known about the treatment effect of adolescence varicocelectomy on long term fertility and paternity rate. Recent studies on outcome of varicocele repair for pain consistently demonstrated a resolution rate of approximately 90% and support varicocele-associated pain as an indication for surgery. Alternate indications for varicocele repair have been proposed in recent decade. Despite the encouraging preliminary data, most studies were uncontrolled retrospective series. Although varicocelectomy may not obviate the need for assisted reproductive techniques in patients with non-obstructive azoospermia, it potentially increases sperm retrieval rate. The significant increase in serum testosterone after varicocelectomy in patients with androgen deficiency may open an alternative treatment for hypogonadism. The adjunctive role of varicocelectomy before assisted reproduction and the significant decrease in sperm DNA fragmentation after varicocele repair deserve further well-designed controlled studies.

A Schematic Overview of the Current Status of Male Infertility Practice

The practice of male infertility has dramatically evolved over the past few decades. This has been achieved after the realization of the important contribution the male counterpart holds in the couple's infertility. It is also supported by a number of breakthroughs in the diagnosis and treatment of this medical condition. Several tests to investigate sperm quality and function were introduced along with refinements and/or institution of novel surgical techniques that can correct several causes of infertility. This manuscript is aimed at highlighting the current state of male infertility practice in a robust, schematic method addressing a broader audience involved in the treatment of male infertility.

Relation between sperm protamine transcripts with global sperm DNA methylation and sperm DNA methyltransferases mRNA in men with severe sperm abnormalities

This study aimed to evaluate the relationship between mRNA expression of DNA methyltransferases (DNMTs) such as DNMT1, DNMT3A and DNMT3B mRNA and sperm global DNA methylation with protamine transcripts in the sperm from men with severe sperm abnormalities. Sperm from each semen sample were isolated using a standard gradient isolation procedure by layering 1 mL of 40% (v/v) density gradient medium over 1 mL of 80% (v/v). A total of 30 oligoasthenoteratozoospermic ejaculates (OAT) and 30 normozoospermic ejaculates as controls were compared using real-time quantitative reverse transcriptase polymerase chain reaction for mRNA expression of DNMT1, 3A, 3B, protamine1 (P1) and protamine2 (P2). The enzyme-linked immunosorbent assay was used to detect global DNA methylation in sperm. A p-value of <0.05 was considered statistically significant. In OAT ejaculates, the increased level of DNMT3A, 3B mRNA, sperm global methylation, P1 plus P2 mRNA and decrease of P1-P2 ratio were significantly different. Also the content of protamine transcript was not correlated with sperm parameters. The increased total protamine transcript levels were associated with increased mRNA methyltransferases. The increase of DNMT1 may lead to an increased level of global methylation.

Role of sperm DNA fragmentation in male factor infertility: A systematic review

OBJECTIVE

To summarise the latest evidence on the role of sperm DNA fragmentation (SDF) in male factor infertility, as SDF has been emerging as a valuable tool for male infertility evaluation.

METHODS

A search of PubMed was conducted using the keywords 'sperm DNA fragmentation' and 'male infertility'. Studies in languages other than English were excluded. All identified studies were screened and clinical studies in humans were included.

RESULTS

In all, 150 articles were included for analysis. Current evidence supports the association between high SDF and poor reproductive outcomes for natural conception and intrauterine insemination. Although the relationship between high SDF and in vitro fertilisation and intracytoplasmic sperm injection is less clear, the negative implication of high SDF on pregnancy loss is evident. Various treatment strategies have been attempted with varying success. The predictive value of SDF testing on outcomes of natural pregnancy and assisted reproduction illustrates its value in clinical practice.

CONCLUSION

The significant role of SDF in male factor infertility is supported by current evidence. The beneficial role of SDF testing in selection of varicocelectomy candidates, evaluation of patients with unexplained infertility and recurrent pregnancy loss, selection of the most appropriate assisted reproductive technique with highest success rate for infertile couples, and assessment of infertile men with modifiable lifestyle factors or gonadotoxin exposure has been recently proposed.

Reproductive outcomes of testicular versus ejaculated sperm for intracytoplasmic sperm injection among men with high levels of DNA fragmentation in semen: systematic review and meta-analysis

OBJECTIVE

To compare sperm DNA fragmentation (SDF) levels between testicular and ejaculated sperm and to evaluate outcomes of intracytoplasmic sperm injection (ICSI) with the use of testicular (Testi-ICSI) versus ejaculated (Ejac-ICSI) sperm in nonazoospermic men with high SDF.

DESIGN

Systematic review and meta-analysis.

SETTING

Not applicable.

PATIENT(S)

Normo- and oligozoospermic men with high levels of SDF in semen subjected to Testi-ICSI or Ejac-ICSI.

INTERVENTION(S)

Summary mean difference (MD) and odds ratio (OR) were calculated with the use of an inverse variance model and fixed- or random-effects models, respectively.

MAIN OUTCOME MEASURE(S)

Primary outcomes were SDF levels, clinical pregnancy rates (CPRs), and live birth rates (LBRs). Secondary outcomes were fertilization and miscarriage rates.

RESULT(S)

Five studies involving 143 patients provided paired SDF rates for testicular and ejaculated sperm, revealing lower SDF in testicular sperm (MD -24.58%). Four studies involving 507 cycles and 3,840 oocytes reported clinical outcomes of Testi-ICSI and Ejac-ICSI. Fertilization rates were not different between sperm sources, but a trend to lower rates was observed with Testi-ICSI. CPRs were higher for Testi-ICSI than for Ejac-ICSI, as were LBRs, whereas miscarriage rates were reduced with Testi-ICSI.

CONCLUSION(S)

Testicular sperm have lower levels of SDF than ejaculated sperm, with Testi-ICSI for high post-testicular SDF men improving reproductive outcomes compared with Ejac-ICSI. Infertile couples may benefit from Testi-ICSI if male partners have confirmed high SDF in the ejaculate.

Sperm DNA fragmentation testing: a cross sectional survey on current practices of fertility specialists

Background

Sperm DNA fragmentation (SDF) testing has been recognized as a valuable tool in the evaluation of infertile men. Despite that, its routine use in clinical practice is still hampered by the lack of understanding of the specific clinical scenarios where SDF testing is most beneficial. The aim of this study was to investigate fertility specialists evaluation of infertility of SDF testing in the context of male infertility evaluation and assisted reproductive technology.

Methods

A questionnaire was developed to survey the major aspects of SDF testing and was mailed to specialists with demonstrated clinical experience in the field of infertility. A total of 65 professionals were invited to answer issues related to the utility of SDF testing, the testing methods they used, were the SDF cut-off values, and the cost of testing and the perceived drawbacks of the test results. Specific clinical scenarios were presented to assess whether or not participants would recommend SDF testing. The frequency of responses was analyzed.

Results

Forty-nine participants from 19 countries responded to the study questionnaire. SDF testing was commonly ordered by 39 (79.6%) respondents; while 10 (20.4%) did not order SDF testing during fertility evaluation. Terminal deoxynucleotidyl transferase nick end labelling (TUNEL) and sperm chromatin structure assay (SCSA) were most commonly utilized (30.6% for both), followed by sperm chromatin dispersion (SCD) (20.4%), single cell gel electrophoresis (Comet) (6.1%) and other methods (12.2%). SDF was most commonly requested in couples presenting with recurrent conventional in vitro fertilization (IVF) failure or pregnancy loss following conventional IVF (91.8%), followed by couples with recurrent first trimester natural pregnancy loss (NPL) and recurrent pregnancy loss (RPL) following intracytoplasmic sperm injection (ICSI) (85.7% for both). A 67.3% of respondents admitted that an SDF test result would affect their decision to utilize testicular instead of ejaculated sperm for ICSI. The reported mean ± standard deviation (SD) cost (USD) of SDF testing was 170.4±122.9. Cost (46.9%), poor validation (36.7%) and low precision (18.3%) were the most commonly reported drawbacks of SDF testing.

Conclusions

SDF testing is utilized in the evaluation of infertility patients by a majority of fertility specialists under specific clinical scenarios. Shortcomings, such as the presence of several SDF testing methods with different cut-off values and the test charges were some of the reasons hampering the routine use of SDF in the evaluation of infertile men.

Clinical utility of sperm DNA fragmentation testing: concise practice recommendations

Sperm DNA integrity is generally acknowledged as an essential component for human reproduction. While the negative impact of high sperm DNA fragmentation (SDF) on outcomes of natural pregnancy and assisted reproductive technology (ART) is well known, the clinical indication of SDF testing is less well defined. A recent review on clinical utility of SDF testing highlighted the different SDF assays and clinical indications of SDF testing. This concise practice recommendations aim at summarizing the evidence and presenting to the readers the essence of the clinical utility of SDF testing based on the currently existing evidence. The potential role of SDF testing in varicocelectomy candidates, couples with recurrent pregnancy loss, patients with unexplained infertility, couples with failed assisted reproduction, and infertile men with exposure to modifiable lifestyle risk factors is illustrated. Recommendations from an expert panel on each clinical condition is presented, with levels of evidence.

A Strengths-Weaknesses-Opportunities-Threats (SWOT) analysis on the clinical utility of sperm DNA fragmentation testing in specific male infertility scenarios

Background

Sperm DNA fragmentation (SDF) is recognized as a leading cause of male infertility because it can impair the paternal genome through distinct pathophysiological mechanisms. Current evidence supports SDF as a major factor in the pathophysiology of several conditions, including varicocele, unexplained infertility, assisted reproductive technology failure, and environmental lifestyle factors, although the mechanisms involved have not been fully described yet. Measurement of the levels of DNA fragmentation in semen provides valuable information on the integrity of paternal chromatin and may guide therapeutic strategies. A recently published clinical practice guideline (CPG) highlighted how to use the information provided by SDF testing in daily practice, which triggered a series of commentaries by leading infertility experts. These commentaries contained an abundance of information and conflicting views about the clinical utility of SDF testing, which underline the complex nature of SDF.

Methods

A search of papers published in response to the CPG entitled “Clinical utility of sperm DNA fragmentation testing: practice recommendations based on clinical scenarios” was performed within the Translational Andrology and Urology (TAU) website (http://tau.amegroups.com/). The start and end dates for the search were May 2017 and August 2017, respectively. Each commentary meeting our inclusion criteria was rated as “supportive without reservation”, “supportive with reservation”, “not supportive” or “neutral”. We recorded whether articles discussed either SDF characteristics as a laboratory test method or clinical scenarios, or both. Subsequently, we extracted the particulars from each commentary and utilized the ‘Strengths-Weaknesses-Opportunities-Threats’ (SWOT) analysis to understand the perceived advantages and drawbacks of SDF as a specialized sperm function method in clinical practice.

Results

Fifty-eight fertility experts from six continents and twenty-two countries contributed commentaries. Overall, participants (87.9%; n=51) were supportive of the recommendations provided by the CPG on the utility of SDF testing based on clinical scenarios. The majority of participants made explicit remarks about both the clinical scenarios and SDF assays’ characteristics. Among ‘not supportive’ and ‘supportive with reservation’ participants, 75% (n=30/40) and 77.5% (n=31/40) expressed concerns related to technical limitations of SDF testing methods and clinical utility of the test in one or more clinical scenarios discussed in the CPG, respectively. The SWOT analysis revealed that the CPG provides a reasonable evidence-based proposal for integration of SDF testing in the routine daily practice. It also uncovered gaps of knowledge and threats limiting the widespread application of SDF in everyday practice, thus allowing the identification of opportunities to further refine SDF testing and its clinical utility.

Conclusions

The understanding of the role of SDF in male infertility requires an in-depth analysis of the multifactorial pathophysiological processes and the theories involved. The SWOT analysis allowed an objective evaluation of CPG on the clinical utility of SDF testing based on clinical scenarios and its accompanying commentaries written by global experts in all possible angles. Implementation of SDF testing in the clinic may not only increase the outcome of ART but more importantly improve the health of both fathers to be and resulting offspring.

The Society for Translational Medicine: clinical practice guidelines for sperm DNA fragmentation testing in male infertility

Sperm DNA fragmentation (SDF) testing has been emerging as a valuable tool for male fertility evaluation. While the essential role of sperm DNA integrity in human reproduction was extensively studied, the clinical indication of SDF testing is less clear. This clinical practice guideline provides recommendations of clinical utility of the test supported by evidence. It is intended to serve as a reference for fertility specialists in identifying the circumstances in which SDF testing should be of greatest clinical value. SDF testing is recommended in patients with clinical varicocele and borderline to normal semen parameters as it can better select varicocelectomy candidates. Outcomes of natural pregnancy and assisted reproductive techniques (ART) can be predicted by result of SDF tests. High SDF is also linked with recurrent pregnancy loss (RPL) and failure of ART. Result of SDF testing may change the management decision by selecting the most appropriate ART with the highest success rate for infertile couples. Several studies have demonstrated the benefit in using testicular instead of ejaculated sperm in men with high SDF, oligozoospermia or recurrent in vitro fertilization (IVF) failure. Infertile men with modifiable lifestyle factor may benefit from SDF testing by reinforcing risk factor modification and monitoring patient's progress to intervention.

Genetics and epigenetics of varicocele pathophysiology: an overview

Varicocele is found in approximately 20% of adults and adolescents and in 19-41% of men seeking treatment for infertility. It is associated with a decrease in sperm count as well as sperm motility and morphology. The currently accepted description of the pathophysiology of varicocele does not explain all its clinical manifestations; therefore, other factors such as genetic and epigenetic changes, associated with the environment, might be involved in causing infertility and decrease in sperm quality. It has been reported that the varicocele-induced deterioration of testicular function is progressive and interferes with fertility; hence, early and efficient assessment of the genetic manifestations in patients would be important for developing future medical interventions. Chromosomal disorders, mutations, polymorphisms, changes in gene expression, and epigenetic changes have all been reported to be associated with varicocele. Several studies are underway to unravel the genetic basis of this disease, as it is important to understand the origin and the aggravating factors to ensure appropriate guidance and intervention. Here, we review the available literature regarding the genetic and epigenetic changes associated with varicocele, and how these alterations are related to the different clinical manifestations of the disease.

Clinical utility of sperm DNA fragmentation testing: practice recommendations based on clinical scenarios

Sperm DNA fragmentation (SDF) has been generally acknowledged as a valuable tool for male fertility evaluation. While its detrimental implications on sperm function were extensively investigated, little is known about the actual indications for performing SDF analysis. This review delivers practice based recommendations on commonly encountered scenarios in the clinic. An illustrative description of the different SDF measurement techniques is presented. SDF testing is recommended in patients with clinical varicocele and borderline to normal semen parameters as it can better select varicocelectomy candidates. High SDF is also linked with recurrent spontaneous abortion (RSA) and can influence outcomes of different assisted reproductive techniques. Several studies have shown some benefit in using testicular sperm rather than ejaculated sperm in men with high SDF, oligozoospermia or recurrent in vitro fertilization (IVF) failure. Infertile men with evidence of exposure to pollutants can benefit from sperm DNA testing as it can help reinforce the importance of lifestyle modification (e.g., cessation of cigarette smoking, antioxidant therapy), predict fertility and monitor the patient’s response to intervention.