Diagnostic accuracy of sperm DNA degradation index (DDSi) as a potential noninvasive biomarker to identify men with varicocele-associated infertility

Effect of varicocele and varicocelectomy on sperm deoxyribonucleic acid fragmentation rates in infertile men with clinical varicocele

Varicocele is the leading cause of male infertility. It can affect sperm quantity and quality through various non-mutually exclusive pathophysiological mechanisms, mainly oxidative stress. Excessive production of reactive oxygen species may overwhelm the sperm's defenses against oxidative stress and harm the sperm's DNA. Excessive sperm DNA breaks, so-called sperm DNA fragmentation, result from the oxidative stress cascade and are commonly found in the ejaculates of men with varicocele and fertility-related issues. Measuring sperm DNA fragmentation can provide valuable information on the extent of harm and might help select candidates for surgical treatment. Varicocelectomy is beneficial for alleviating oxidative stress-associated infertility and improving sperm DNA integrity. However, reproductive outcomes of infertile men with elevated sperm DNA fragmentation rates and surgically treated varicoceles remain poorly studied, and there is a need for well-designed trials to determine the impact of sperm DNA fragmentation reduction on natural and medically assisted reproduction.

A systematic review identifying fertility biomarkers in semen: a clinical approach through Omics to diagnose male infertility

OBJECTIVE

To identify the most robust molecular biomarkers in sperm and seminal plasma for the diagnosis of male infertility, and to evaluate their clinical use.

DESIGN

Systematic review.

SETTING

Not applicable.

PATIENT(S)

Accessible studies reporting well-defined (in)fertile populations and semen molecular biomarkers were included in this review.

INTERVENTION(S)

A systematic search of the literature published in MEDLINE-PubMed and EMBASE databases was performed, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

MAIN OUTCOME MEASURE(S)

The primary outcome was the content, expression, or activity of molecular biomarkers in human semen samples. Only studies reporting a receiver-operating characteristic (ROC) analysis values were included.

RESULT(S)

Eighty-nine studies were included. Direct evaluation of sperm DNA damage has high potential as a diagnostic biomarker of fertility and assisted reproductive technology outcomes (area under the curve [AUCs] median = 0.67). Regarding strand break-associated chromatin modifications, γH2AX levels show good predictive value for the diagnosis of male infertility (AUCs median = 0.93). Some noncoding ribonucleic acid (RNA) exhibit excellent predictive values; miR-34c-5p in semen is the most well-characterized and robust transcriptomic biomarker (AUCs median = 0.78). While many proteins in semen show fair diagnostic value for sperm quality and fertilizing capacity, the levels of some, such as TEX101, in seminal plasma have an excellent diagnostic potential (AUCs median = 0.69). Although individual metabolites and metabolomic profiles in seminal plasma present good predictive value, the latter seem to be better than the former when inferring sperm quality and fertilizing capacity.

CONCLUSION(S)

The current review supports that some Omics (e.g., DNA structure and integrity, genomics and epigenomics, transcriptomics, metabolomics, and proteomics) could be considered relevant molecular biomarkers that may help identify infertility etiologies and fertilization prognosis with cost-effective, simple, and accurate diagnosis.

Sperm DNA fragmentation in reproductive medicine: A review

Approximately 15% of the world's couples suffer from infertility during their reproductive period of which the male factor is responsible for 50% of cases. Male factor infertility is multifactorial in origin, and sperm DNA fragmentation (SDF) has also been linked to male infertility including idiopathic male infertility. Some degree of controlled DNA nicking is essential for adequate DNA compaction, but excessive SDF is usually associated with reduced male fertility potential, reduced fertilisation, poor embryo quality, recurrent pregnancy loss and poor assisted reproductive techniques (ARTs) outcomes. Although semen analysis remains the gold standard for diagnosis of male factor infertility worldwide, its limitations motivated the search and the development of complementary tests of sperm function and integrity. SDF assay is an emerging diagnostic tool in infertile men, and several indications for SDF testing in infertile couples have also been proposed. The use of SDF in routine male infertility assessment is, however, still controversial. Furthermore, both direct and indirect SDF tests are now available. Hence, the present review was conducted to summarise the recent evidence of SDF, underlying mechanisms, clinical indications, diagnostic tests, as well as the role of SDF in male factor infertility, pregnancy and ART outcomes.

Direct but Not Indirect Methods Correlate the Percentages of Sperm With Altered Chromatin to the Intensity of Chromatin Damage

Although sperm chromatin damage, understood as damage to DNA or affectations in sperm protamination, has been proposed as a biomarker for sperm quality in both humans and livestock, the low incidence found in some animals raises concerns about its potential value. In this context, as separate methods measure different facets of chromatin damage, their comparison is of vital importance. This work aims at analyzing eight techniques assessing chromatin damage in pig sperm. With this purpose, cryopreserved sperm samples from 16 boars were evaluated through the following assays: TUNEL, TUNEL with decondensation, SCSA, alkaline and neutral sperm chromatin dispersion (SCD) tests, alkaline and neutral Comet assays, and chromomycin A3 test (CMA3). In all cases, the extent of chromatin damage and the percentage of sperm with fragmented DNA were determined. The degree of chromatin damage and the percentage of sperm with fragmented DNA were significantly correlated (p < 0.05) in direct methods (TUNEL, TUNEL with decondensation, and alkaline and neutral Comet) and CMA3, but not in the indirect ones (SCD and SCSA). Percentages of sperm with fragmented DNA determined by alkaline Comet were significantly (p < 0.05) correlated with TUNEL following decondensation and CMA3; those determined by neutral Comet were correlated with the percentage of High DNA Stainability (SCSA); those determined by SCSA were correlated with neutral and alkaline SCD; and those determined by neutral SCD were correlated with alkaline SCD. While, in pigs, percentages of sperm with fragmented DNA are directly related to the extent of chromatin damage when direct methods are used, this is not the case for indirect techniques. Thus, the results obtained herein differ from those reported for humans in which TUNEL, SCSA, alkaline SCD, and alkaline Comet were found to be correlated. These findings may shed some light on the interpretation of these tests and provide some clues for the standardization of chromatin damage methods.

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.

An update on the techniques used to measure oxidative stress in seminal plasma

Reactive oxygen species (ROS) are produced in significant amounts by spermatozoa and leucocytes. They are necessary to carry out various physiological functions such as sperm capacitation, hyperactivation, acrosome reaction, sperm-zona binding and cellular signalling pathways. Oxidative stress (OS) results when the ROS levels overwhelm the available antioxidant reserve. A number of direct and indirect tests have been developed to assess oxidative stress. In this manuscript, we discuss these common direct and indirect tests as well as their advantages and disadvantages. Tests measuring sperm dysfunction secondary to oxidative stress such as lipid peroxidation, DNA fragmentation and protein alterations are also described.

Proteomic Analysis in Seminal Plasma of Fertile Donors and Infertile Patients with Sperm DNA Fragmentation

Seminal plasma proteomics studies could represent a new approach for the determination of molecular elements driving male infertility, resulting in a better male infertility characterization. The aim of this study is to investigate proteomic differences in seminal plasma samples from fertile and infertile individuals. For that, semen samples were selected according to semen analysis, clinical pathology, and values of sperm DNA fragmentation (alkaline and neutral Comet assay and Sperm Chromatin Dispersion test). A total of 24 seminal plasma samples classified in four groups were processed: fertile donors (FD), recurrent miscarriage patients (RM), asthenoteratozoospermic patients (ATZ), and asthenoteratozoospermic patients with varicocele (ATZ-VAR). Results obtained by 2D-differential gel electrophoresis (2D-DIGE) revealed 26 spots significantly increased in fertile donors when compared to patient groups. Also, eight spots in the ATZ group and two in the ATZ-VAR group were decreased compared to the other groups. Twenty-eight proteins were identified by mass spectrometry (MS), most of them involved in metabolic and cellular processes and with a catalytic or binding function. Protein-protein interactions through Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) tool suggest that a large part of them were associated with each other. Furthermore, most of them were associated with ubiquitin C, indicating that it could play an important regulation role, resulting in a potential male infertility biomarker.

Is there a role for phosphodiesterase inhibitors in the treatment of male subfertility?

Intracytoplasmic sperm injection (ICSI) is frequently used to overcome severe deficits in semen quality. Concerns, however, are arising over its increasing use for non-male factor infertility. Moreover, increased risk of cardiovascular disease, congenital abnormalities, aneuploidies and childhood cancers have all been reported in the literature in relation to ICSI and it is possible that the quality of sperm chosen for injection may be an important factor in these unwanted outcomes. Given the wider adoption of ICSI to treat beyond the requirements of male infertility alone, research focussed on alternative methods to diagnose and treat the infertile couple is gaining increasing attention. This review focuses on the information available to date on the use of non-selective phosphodiesterase inhibitors (PDEI), specifically pentoxifylline (PF), caffeine (CF) and theophylline (TP) to stimulate sperm motility, thereby potentially reducing the need for ICSI in certain patient groups who may benefit from either expectant management or from a less stressful, minimally invasive and inexpensive treatment such as intrauterine insemination (IUI). The review focuses firstly on the mechanism of action of PDEI followed by treatment effects on sperm parameters such as motility and hyperactivated motility and sperm DNA integrity. Specific clinical implications are discussed that outline the potential role of PDEI in clinical practice and highlights areas in need of further research.

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.

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

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

Conventional semen analysis and advanced sperm function tests in diagnosis and management of varicocele

Clinical varicoceles are a common cause of male infertility and affect sperm parameters as measured in a conventional semen analysis. Varicocelectomy has been shown in prospective studies to improve semen parameters in men with a clinical varicocele. Clinical varicoceles are also a well-known source of oxidative stress which may affect the quality of spermatozoa. Spermatozoa are particularly susceptible to oxidative stress due to a limited capacity for DNA repair. The susceptibility of spermatozoa to oxidative stress is modulated by a balance between ROS and antioxidants, which can be quantified by various laboratory assays. Varicocelectomy has been consistently shown to reduce both ROS and sperm DNA fragmentation, and various assays should be utilised in the diagnosis and treatment of infertile men with a clinical varicocele.

Oxidative stress in the pathophysiology of male infertility

The effects of reactive oxygen species on male fertility are governed by the oxidative paradox, defined by a delicate balance between oxidative stress and antioxidant capacity. When regulated appropriately, reactive oxygen species ensure effective function; however, when uninhibited, they represent key players in male factor infertility. Mechanisms responsible for this include oxidative destruction of sperm lipid membranes, damage to gamete DNA both by gene mutation and by direct breakdown of the DNA backbone, mitochondrial dysfunction and apoptotic cell death. Utilizing various male pathologies as case studies, we see ways in which oxidative stress has the potential to impact fertility in a negative way. Varicocele, erectile dysfunction, testicular cancer and even idiopathic male infertility highlight common mechanistic pathways, as well as subtle variations in the ways reactive oxygen species can operate. Oxidative biomarkers have emerged to better study male infertility, predict reproductive success and modify assisted reproductive technologies to minimize oxidative stress.

Are specialized sperm function tests clinically useful in planning assisted reproductive technology?

40-year-old male patient and 32-year-old female partner, with a history of primary infertility of two years duration. The workup revealed idiopathic mild oligoasthenotheratozoospermia, and no apparent female infertility factors. The couple has failed three intrauterine insemination (IUI) cycles, planning more IUI cycles but also considering in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI).

The incidence and etiology of sperm DNA fragmentation in the ejaculates of males with spinal cord injuries

STUDY DESIGN

Retrospective descriptive study.

OBJECTIVES

To determine the incidence and probable etiology of sperm DNA fragmentation (SDF) in a sample of males with spinal cord injury (SCI).

SETTING

Hospital in Toledo, Spain; University-based Genetics laboratory in Madrid, Spain.

METHODS

Semen collected by vibro-stimulation from 27 males with various levels of spinal cord injury. Classical semen parameters, SDF, leukocytospermia and pro-oxidant capacity were assessed and compared with a cohort of normozoospermic fertile donors (n = 10).

RESULTS

Males with SCI presented with lower semen quality compared with normozoospermic donors with respect to progressive motility (p = 0.0002), SDF (p < 0.00005), pro-oxidant capacity (p = 0.0191) and leukocytospermia (p < 0.00005). Although there was no significant correlation between semen quality and time since the lesion occurred, the period of abstinence appeared to be positively correlated with SDF (r = 0.486; p = 0.041). When the semen parameters of males with SCI were categorized based on those with cervical and thoracic lesions, sperm concentration was higher for those with cervical damage (p = 0.0257). Males with complete lesions (AIS A) had ejaculates that were lower in progressive motility (p = 0.0040) than those with incomplete injuries (AIS B-D).

CONCLUSIONS

Ejaculates of males with SCI have excessively elevated SDF when compared with normozoospermic donors, which is likely to be associated with coincident high levels of leucocytospermia and pro-oxidant capacity. We propose that these phenomena are caused by the accumulation and degeneration of spermatozoa in the cauda epididymidis.

Does varicocelectomy improve semen in men with azoospermia and clinically palpable varicocele?

The effectiveness of varicocelectomy in nonobstructive azoospermia is controversial. The current study assessed the efficacy of microsurgical subinguinal varicocelectomy in nonobstructive azoospermic men with palpable varicocele and to evaluate predictive parameters of outcome. We reviewed the records of 723 patients who had microsurgical varicocelectomy and diagnostic testicular biopsy between 2012 and 2016 at a tertiary medical centre. Data pertaining to the physical, laboratory (semen analysis and hormonal profile) and histopathology features were examined, exploring the predictors of improvement in semen analysis post-varicocelectomy. In total, 42 patients with mean age 35.71 ± 6.35 years were included. After a mean varicocelectomy follow-up of 6.7 months, motile spermatozoa in the ejaculate could be observed in 11 patients (26.2). Out of all the factors examined, only testicular histopathology significantly predicted post-varicocelectomy outcome, where 8/11 patients exhibited hypospermatogenesis, and 3/11 Sertoli cell-only regained spermatozoa in semen. Microsurgical varicocelectomy in nonobstructive azoospermic men with clinically palpable varicocele can result in sperm appearance in the ejaculate with the highest success expected in hypospermatogenesis.

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.

Intracytoplasmic sperm injection for male infertility and consequences for offspring

Intracytoplasmic sperm injection (ICSI) has become the most commonly used method of fertilization in assisted reproductive technology. The primary reasons for its popularity stem from its effectiveness, the standardization of the procedure, which means that it can easily be incorporated into the routine practice of fertility centres worldwide, and the fact that it can be used to treat virtually all forms of infertility. ICSI is the clear method of choice for overcoming untreatable severe male factor infertility, but its (over)use in other male and non-male factor infertility scenarios is not evidence-based. Despite all efforts to increase ICSI efficacy and safety through the application of advanced sperm retrieval and cryopreservation techniques, as well as methods for selecting sperm with better chromatin integrity, the overall pregnancy rates from infertile men remain suboptimal. Treating the underlying male infertility factor before ICSI seems to be a promising way to improve ICSI outcomes, but data remain limited. Information regarding the health of ICSI offspring has accumulated over the past 25 years, and there are reasons for concern as risks of congenital malformations, epigenetic disorders, chromosomal abnormalities, subfertility, cancer, delayed psychological and neurological development, and impaired cardiometabolic profile have been observed to be greater in infants born as a result of ICSI than in naturally conceived children. However, as subfertility probably influences the risk estimates, it remains to be determined to what extent the observed adverse outcomes are related to parental factors or associated with ICSI.

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.

Use of testicular sperm for intracytoplasmic sperm injection in men with high sperm DNA fragmentation: a SWOT analysis

Spermatozoa retrieved from the testis of men with high levels of sperm DNA fragmentation (SDF) in the neat semen tend to have better DNA quality. Given the negative impact of SDF on the outcomes of Assisted Reproductive Technology (ART), an increased interest has emerged about the use of testicular sperm for intracytoplasmic sperm injection (Testi-ICSI). In this article, we used a SWOT (strengths, weaknesses, opportunities, and threats) analysis to summarize the advantages and drawbacks of this intervention. The rationale of Testi-ICSI is bypass posttesticular DNA fragmentation caused by oxidative stress during sperm transit through the epididymis. Hence, oocyte fertilization by genomically intact testicular spermatozoa may be optimized, thus increasing the chances of creating a normal embryonic genome and the likelihood of achieving a live birth, as recently demonstrated in men with high SDF. However, there is still limited evidence as regards the clinical efficacy of Testi-ICSI, thus creating opportunities for further confirmatory clinical research as well as investigation of Testi-ICSI in clinical scenarios other than high SDF. Furthermore, Testi-ICSI can be compared to other laboratory preparation methods for deselecting sperm with damaged DNA. At present, the available literature supports the use of testicular sperm when performing ICSI in infertile couples whose male partners have posttesticular SDF. Due to inherent risks of sperm retrieval, Testi-ICSI should be offered when less invasive treatments for alleviating DNA damage have failed. A call for continuous monitoring is nonetheless required concerning the health of generated offspring and the potential complications of sperm retrieval.

Reduced sperm telomere length in individuals with varicocele is associated with reduced genomic integrity

Varicocele, defined as enlarged varicose veins in the scrotum, is the most common identifiable cause of male infertility. There are significant correlations between oxidative stress and varicocele-related infertility due to testicular hyperthermia, which can result in low sperm function. In addition, recent excessive oxidative stress can affect sperm telomere length and integrity of sperm DNA. Therefore, we assessed sperm telomere length as a potential marker of paternal genome integrity and leukocyte telomere length as an internal control (real-time PCR), along with sperm chromatin status (TUNEL and chromomycin A3 assay), and lipid peroxidation (Bodipy probe) in 18 infertile men with grade II or III varicocele, and 20 fertile men. Means of sperm parameters, sperm and leukocyte telomere length were significantly lower, while means of sperm DNA fragmentation, protamine deficiency, and lipid peroxidation were significantly higher in infertile men with varicocele compared to fertile men. Therefore, shortened telomere length in sperm and leukocytes is likely associated with increased oxidative stress related to the state of varicocele, which also accounts for increase in sperm DNA fragmentation. Thus, assessment of leukocyte telomere length could be taken as an indicator of antioxidant capacity in an individual, which also affects sperm function.

Dynamic assessment of human sperm DNA damage I: the effect of seminal plasma-sperm co-incubation after ejaculation

AIM

The purpose of the study was to evaluate the impact of seminal plasma in human ejaculates on the sperm DNA quality and DNA longevity.

METHODS

Semen samples for this study were obtained from 20 donors with a normal spermiogram. Following centrifugation, the sperm pellet was resuspended either in the seminal plasma proceeding from its respective donor, or in an equal amount of PBS, adjusting the concentration to 50 × 10⁶/ml. Each set of samples was incubated at 37 °C for 24 h and the sperm DNA damage was assessed using the chromatin-dispersion test following 0, 2, 6, and 24 h of incubation.

RESULTS

Sperm DNA fragmentation (SDF) did not differ between the two experimental conditions at T0; however, Kaplan-Meier estimates to test for survival showed an statistical significant increase of SDF in the seminal plasma group when compared to the PBS group following all timeframes (p 0.000). With respect to sperm DNA longevity, the most dramatic loss of sperm DNA quality occurred during the first 2 h of incubation, with the rate of SDF (rSDF) in the seminal plasma being 2.1 more intense than in PBS. Interestingly, the rSDF was found to vary significantly between individuals, which was confirmed with significant correlations in all rSDF timeframes (rSDF T0-2, p 0.049; rSDF T2-6, p 0.000; rSDF T6-24: p 0.000).

CONCLUSIONS

Co-incubation of semen samples in seminal plasma after ejaculation increases iatrogenic sperm damage. This effect is statistically significant after 2 h of co-incubation. Subsequently, for ART purposes seminal plasma must be quickly removed after ejaculation-liquefaction, to avoid a higher susceptibility of sperm DNA towards fragmentation.

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.

Developing a deeper insight into reproductive biomarkers

The development of biomarkers of reproductive medicine is still in its infancy because many black boxes are still present in reproductive medicine. Novel approaches to human infertility diagnostics and treatment must be developed because reproductive medicine has lagged behind in the implementation of biomarkers in clinical medicine. Despite the dearth of the available literature, the current rapid pace of publications suggests that this gap will soon be filled therefore; this review is a précis of the research that has been done so far and will provide a basis for the development of biomarkers in reproductive medicine.

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.

The impact of coexisting sperm DNA fragmentation and seminal oxidative stress on the outcome of varicocelectomy in infertile patients: A prospective controlled study

OBJECTIVES

To study the relationship between sperm DNA fragmentation (SDF) and reactive oxygen species (ROS) levels in infertile patients with varicocele, and to examine the beneficial effect of varicocelectomy and elucidate predictors of improvement after repair.

PATIENTS SUBJECTS AND METHODS

We prospectively studied 60 patients with varicocele and abnormal semen variables who attended the outpatient clinic complaining of infertility for ≥12 months. In all, 25 patients (41.7%) had bilateral varicoceles and 35 (58.3%) had left varicoceles. The DNA fragmentation index (DFI%, percentage of sperm with denatured nuclei), ROS and total non-enzymatic antioxidant capacity (TAC) were measured. Inguinal varicocelectomy was performed in all patients. At 3-6 months postoperatively, all measurements were repeated. A control group, comprised of 20 normozoospermic fertile men, was included. Regression analysis was used to examine predictors of improvement.

RESULTS

The mean (SD) DFI% in the 60 infertile patients with varicocele was 29.9 (8.3) and 7.56 (2.84)% in the controls; ROS levels were 4.49 (0.9) in patients and 2.62 (0.8) photons/min in controls; and the TAC was 0.97 (0.4) in patients and 1.5 (0.5) mM in controls; with highly significant differences between the patients and controls. The DFI% showed a positive correlation with ROS levels, whilst the total motile sperm count (TMSC) had a significant negative correlation with DFI%, ROS levels and grade of varicocele, whilst there was significant positive correlation with TAC. The grade of varicocele and duration of infertility were related to the presence of higher levels of ROS and increased of DFI%. Postoperatively, improvement (measured as a >50% increase in TMSC) occurred in 40 of 55 (73%) patients available at follow-up, with a significant reduction in the mean (SD) DFI% from 29.49 (8.58) to 18.78 (7.23)%, ROS levels from 4.49 (0.88) to 3.27 (1.3) photons/min (both P < 0.001), and a significant increase in the mean (SD) TAC from 1.01 (0.44) to 2.05 (0.51) mM (P < 0.001). Responders had a shorter infertility duration and lower preoperative DFI% and ROS levels. Regression analysis showed that DFI% is a predictor of improvement after varicocelectomy.

CONCLUSION

SDF was shown to have a negative impact on improvement after varicocelectomy. Hence, DFI% could be recommended as a prognostic test in infertile patients with varicocele to help decision-making as regards the necessity and the anticipated outcome of varicocelectomy in patients with infertility.

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.

Outcome of varicocele repair in men with nonobstructive azoospermia: systematic review and meta-analysis

The objective of this systemic review was to evaluate the benefit of repairing clinical varicocele in infertile men with nonobstructive azoospermia (NOA). The surgically obtained sperm retrieval rate (SRR) and pregnancy rates following assisted reproductive technology (ART) with the use of retrieved testicular sperm were the primary outcomes. The secondary outcomes included the presence of viable sperm in postoperative ejaculate to avoid the testicular sperm retrieval and pregnancy rates (both assisted and unassisted) using postoperative ejaculated sperm. An electronic search to collect the data was performed using the MEDLINE and EMBASE databases until April 2015. Eighteen studies were included in this systematic review and accounted for 468 patients who were diagnosed with NOA and varicocele. These patients were subjected to either surgical varicocele repair or percutaneous embolization. Three controlled studies evaluating sperm retrieval outcomes indicated that in patients who underwent varicocelectomy, SRR increased compared to those without varicocele repair (OR: 2.65; 95% CI: 1.69–4.14; P < 0.001). Although pregnancy rates with the use of testicular sperm favored the varicocelectomy group, results were not statistically significant (clinical pregnancy rate OR: 2.07; 95% CI: 0.92–4.65; P = 0.08; live birth rate OR: 2.19; 95% CI: 0.99–4.83; P = 0.05). The remaining fifteen studies reported postoperative semen analysis results. In 43.9% of the patients (range: 20.8%–55.0%), sperm were found in postoperative ejaculates. Pregnancy rates for unassisted and assisted (after IVF/ICSI) were 13.6% and 18.9% in the group of men with sperm in postoperative ejaculates, respectively. Our findings indicate that varicocelectomy in patients with NOA and clinical varicocele is associated with improved SRR. In addition, approximately 44% of the treated men will have enough sperm in the ejaculate to avoid sperm retrieval. Limited data on pregnancy outcomes with both postoperative ejaculated sperm and harvested testicular sperm preclude any firm conclusion with regard to the possible increased fertility potential in treated individuals. In conclusion, the results of our study indicate that infertile men with NOA and clinical varicocele benefit from varicocelectomy. Given the low/moderate quality of evidence available, it is advisable that doctors discuss with their patients with NOA the risks and benefits of varicocele repair.

Summary evidence on the effects of varicocele treatment to improve natural fertility in subfertile men

The objective of this review was to summarize the evidence concerning the benefit of varicocele treatment to improve natural fertility in subfertile males. We also analyzed the effect of varicocele treatment on conventional semen parameters and sperm functional tests. An electronic search to collect the data was performed using the PubMed/MEDLINE databases until July 2015. Data pooled from a variety of study designs indicate that varicocelectomy improves semen parameters in the majority of the treated men with clinical varicocele and abnormal semen parameters regardless of the chosen surgical method. Surgical varicocele repair was beneficial not only for alleviating oxidative stress-associated infertility but also to improve sperm nuclear DNA integrity. However, given the low magnitude of the effect size in sperm DNA integrity, further research is needed to elucidate its clinical significance. Conflicting results on the effect of varicocele treatment on natural fertility seem to be due to heterogeneous study designs and, more importantly, patient selection criteria. When these issues are controlled, current evidence indicates that treatment of subclinical varicocele is not warranted, as it does not seem to improve fertility. On the contrary, fair evidence indicates that varicocele treatment should be offered to infertile patients with palpable varicocele and abnormal semen parameters. This evidence supports the current guidelines issued by the American Urological Association and European Association of Urology, which state that varicocele treatment should be offered to male partners of infertile couples presenting for evaluation with clinical varicocele and semen parameters alterations.

Specialized sperm function tests in varicocele and the future of andrology laboratory

Varicocele is a common medical condition entangled with many controversies. Though it is highly prevalent in men with infertility, still it marks its presence in males who do have normal fertility. Determining which patients are negatively affected by varicocele would enable clinicians to better select those men who benefitted the most from surgery. Since conventional semen analysis has been limited in its ability to evaluate the negative effects of varicocele on fertility, a multitude of specialized laboratory tests have emerged. In this review, we examine the role and significance of specialized sperm function tests with regards to varicocele. Among the various tests, analysis of sperm DNA fragmentation and measurements of oxidative stress markers provide an independent measure of fertility in men with varicocele. These diagnostic modalities have both diagnostic and prognostic information complementary to, but distinct from conventional sperm parameters. Test results can guide management and aid in monitoring intervention outcomes. Proteomics, metabolomics, and genomics are areas; though still developing, holding promise to revolutionize our understanding of reproductive physiology, including varicocele.

Effect of varicocele on semen characteristics according to the new 2010 World Health Organization criteria: a systematic review and meta-analysis

This study investigated the effects of varicocele on semen parameters in infertile men based on the new 2010 World Health Organization laboratory manual for the examination of human semen. Semen analysis results (volume, sperm count, motility, and morphology) were the primary outcomes. An electronic search to collect the data was conducted using the Medline/PubMed, SJU discover, and Google Scholar databases. We searched articles published from 2010 to August 2015, i.e., after the publication of the 2010 WHO manual. We included only those studies that reported the actual semen parameters of adult infertile men diagnosed with clinical varicocele and contained a control group of either fertile men or normozoospermic men who were not diagnosed with varicocele. Ten studies were included in the meta-analysis, involving 1232 men. Varicocele was associated with reduced sperm count (mean difference: −44.48 × 10⁶ ml⁻¹; 95% CI: −61.45, −27.51 × 10⁶ ml⁻¹; P < 0.001), motility (mean difference: −26.67%; 95% CI: −34.27, −19.08; P < 0.001), and morphology (mean difference: −19.68%; 95% CI: −29.28, −10.07; P < 0.001) but not semen volume (mean difference: −0.23 ml; 95% CI: −0.64, 0.17). Subgroup analyses indicated that the magnitude of effect was influenced by control subtype but not WHO laboratory manual edition used for semen assessment. We conclude that varicocele is a significant risk factor that negatively affects semen quality, but the observed pooled effect size on semen parameters does not seem to be affected by the WHO laboratory manual edition. Given most of the studies published after 2010 still utilized the 1999 manual for semen analysis, further research is required to fully understand the clinical implication of the 2010 WHO laboratory manual on the association between varicocele and semen parameters.