Clinical utility of sperm DNA fragmentation testing: concise practice recommendations

Sperm DNA Fragmentation: Unraveling Its Imperative Impact on Male Infertility Based on Recent Evidence

Male factors may be present in up to 50-70% of infertile couples and the prevalence of male infertility accounts for 20-30% of infertility cases. Understanding the mechanisms and causes behind male infertility remains a challenge, but new diagnostic tools such as DNA fragmentation might aid in cases where the routine semen analysis is insufficient. DNA fragmentation, which refers to damages or breaks of the genetic material of the spermatozoa, is considered one of the main causes of male infertility due to impaired functional capability of sperm. The aim of the present narrative review is to investigate and enlighten the potential correlation between DNA fragmentation and male infertility parameters such as the seminal profile and the reproductive outcomes. Comprehensive research in PubMed/Medline and Scopus databases was conducted and 28 studies were included in the present review. Fourteen studies provided data regarding the impact of DNA fragmentation and seminal parameters and showed a correlation of significantly lower sperm count, lower concentration, motility, and abnormal morphology with an increased DNA fragmentation index (DFI). Similarly, 15 studies provided data regarding the impact of DFI on reproductive outcomes. Two studies showed higher aneuploidy rates with higher DFI values, and seven studies showed significantly lower pregnancy rates and live birth rates with higher DFI values. Ultimately, the studies included in this review highlight, collectively, the importance of measuring sperm DFI in the assessment of male infertility. Further studies are needed to explore the effectiveness of interventions aiming to reduce DFI levels.

Technical Aspects and Clinical Limitations of Sperm DNA Fragmentation Testing in Male Infertility: A Global Survey, Current Guidelines, and Expert Recommendations

PURPOSE

Sperm DNA fragmentation (SDF) is a functional sperm abnormality that can impact reproductive potential, for which four assays have been described in the recently published sixth edition of the WHO laboratory manual for the examination and processing of human semen. The purpose of this study was to examine the global practices related to the use of SDF assays and investigate the barriers and limitations that clinicians face in incorporating these tests into their practice.

MATERIALS AND METHODS

Clinicians managing male infertility were invited to complete an online survey on practices related to SDF diagnostic and treatment approaches. Their responses related to the technical aspects of SDF testing, current professional society guidelines, and the literature were used to generate expert recommendations via the Delphi method. Finally, challenges related to SDF that the clinicians encounter in their daily practice were captured.

RESULTS

The survey was completed by 436 reproductive clinicians. Overall, terminal deoxynucleotidyl transferase deoxyuridine triphosphate Nick-End Labeling (TUNEL) is the most commonly used assay chosen by 28.6%, followed by the sperm chromatin structure assay (24.1%), and the sperm chromatin dispersion (19.1%). The choice of the assay was largely influenced by availability (70% of respondents). A threshold of 30% was the most selected cut-off value for elevated SDF by 33.7% of clinicians. Of respondents, 53.6% recommend SDF testing after 3 to 5 days of abstinence. Although 75.3% believe SDF testing can provide an explanation for many unknown causes of infertility, the main limiting factors selected by respondents are a lack of professional society guideline recommendations (62.7%) and an absence of globally accepted references for SDF interpretation (50.3%).

CONCLUSIONS

This study represents the largest global survey on the technical aspects of SDF testing as well as the barriers encountered by clinicians. Unified global recommendations regarding clinician implementation and standard laboratory interpretation of SDF testing are crucial.

Sperm DNA fragmentation and its interaction with female factors

High levels of sperm deoxyribonucleic acid (DNA) fragmentation have been associated with adverse reproductive outcomes, including low natural and assisted pregnancy rates, abnormal embryonic development, and recurrent pregnancy loss. These poor outcomes are likely caused by unrepaired DNA damage exceeding a critical repair threshold, adversely affecting normal embryo development. In these cases, DNA repair mechanisms of the oocyte may play a significant role in compensating for sperm DNA damage, preserving normal embryo development, and enhancing reproductive outcomes.

Micronutrient supplements as antioxidants in improving sperm quality and reducing DNA fragmentation

BACKGROUND

Spermatogenesis and sperm quality may be negatively impacted by an increase in reactive oxygen species. This study investigates the efficacy of combined antioxidant therapy for treating male infertility, as measured by semen analyses and the sperm DNA fragmentation index (DFI). Infertile men with a high sperm DNA fragmentation index were instructed to take two oral micronutrient capsules daily for three months. Each antioxidant formulation contained 60 mg vitamin E, 400 µg folic acid, 30 mg selenium, 125 mg L-arginine, 220 mg L-carnitine, 7.5 mg coenzyme Q10, 40 mg L-glutathione, and 20 mg zinc citrate. At entry and post-treatment, the general characteristics, semen analysis, and sperm chromatin dispersion assays were recorded and compared.

RESULTS

After three months of treatment with antioxidant compounds, the quality of spermatozoa improved significantly, as indicated by a decrease in the mean DNA fragmentation index from 45.6 ± 17.2% to 34.8 ± 20.3%; an increase in sperm concentration from 29.7 × 106/mL to 35.7 × 106/mL (p < 0.001), an increase in a total number of spermatozoa from 72.1 × 106 to 95.5 × 106 (p = 0.012), and an increase in the vitality from 75.5 ± 17.1 to 81.1 ± 14.4% viable forms (p < 0.001).

CONCLUSIONS

Micronutrient supplementation can improve sperm quality and DNA integrity in infertile men. Men with infertility and significant sperm DNA fragmentation who take antioxidants for three months experience a reduction in DNA fragmentation index and an increase in sperm quality as measured by the semen analysis.

TRIAL REGISTRATION

NCT04509583 . Registered 12 August 2020, Hue University of Medicine and Pharmacy Ethics Committee-Retrospectively registered.

Smoking and Its Consequences on Male and Female Reproductive Health

Smoking contributes to the death of around one in 10 adults worldwide. Specifically, cigarettes are known to contain around 4000 toxins and chemicals that are hazardous in nature. The negative effects of smoking on human health and interest in smoking-related diseases have a long history. Among these concerns are the harmful effects of smoking on reproductive health. Thirteen percent of female infertility is due to smoking. Female smoking can lead to gamete mutagenesis, early loss of reproductive function, and thus advance the time to menopause. It has been also associated with ectopic pregnancy and spontaneous abortion. Even when it comes to assisted reproductive technologies cycles, smokers require more cycles, almost double the number of cycles needed to conceive as non-smokers. Male smoking is shown to be correlated with poorer semen parameters and sperm DNA fragmentation. Not only active smokers but also passive smokers, when excessively exposed to smoking, can have reproductive problems comparable to those seen in smokers. In this book chapter, we will approach the effect of tobacco, especially tobacco smoking, on male and female reproductive health. This aims to take a preventive approach to infertility by discouraging smoking and helping to eliminate exposure to tobacco smoke in both women and men.

Impact of heavy alcohol consumption and cigarette smoking on sperm DNA integrity

The purposes of the presents study were to investigate the impact of alcohol consumption and cigarette smoking on semen parameters and sperm DNA quality, as well as to determine whether tobacco smoking, or alcohol consumption causes more deterioration of sperm quality. Two hundred and eleven semen samples of men were included in this study. Four groups were studied: heavy smokers (N = 48), heavy drinkers (N = 52), non-smokers (n = 70), and non-drinkers (n = 41). Semen parameters were determined according to WHO guidelines, protamine deficiency assessed by chromomycin (CMA3) staining, and sperm DNA fragmentation (sDF) evaluated by TUNEL assay. Sperm parameters were significantly higher in non-smokers versus smokers and in non-drinkers versus drinkers (p < 0.005). However, protamine deficiency and sDF were significantly lower in non-smokers versus smokers and in non-drinkers versus drinkers (p < 0.0001). No significant difference in the semen analysis parameters was observed between heavy smokers and heavy drinkers (semen volume: 3.20 ± 1.43 vs. 2.81 ± 1.56 ml, semen count: 65.75 ± 31.32 vs. 53.51 ± 32.67 mill/ml, total motility: 24.27 ± 8.18 vs. 23.75 ± 1.75%, sperm vitality: 36.15 ± 18.57 vs. 34.62 ± 16.65%, functional integrity: 41.56 ± 18.57 vs. 45.96 ± 17.98% and the morphologically normal spermatozoa: 28.77 ± 11.82 vs. 27.06 ± 13.13%, respectively). However, protamine deficiency was significantly higher among drinkers than smokers (37.03 ± 9.75 vs. 33.27 ± 8.56%, p = 0.020). The sDF was also significantly higher among drinkers than smokers (22.37 ± 7.60 vs. 15.55 ± 3.33%, p < 0.0001). Thus, cigarette smoking, and heavy alcohol intake can deteriorate sperm quality. However, alcohol consumption deteriorates sperm maturity and damages DNA integrity at significantly higher rates than cigarette smoking.

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.

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.

European Association of Urology Guidelines Panel on Male Sexual and Reproductive Health: A Clinical Consultation Guide on the Indications for Performing Sperm DNA Fragmentation Testing in Men with Infertility and Testicular Sperm Extraction in Nonazoospermic Men

Accumulating evidence has highlighted the contribution of oxidative stress and sperm DNA fragmentation (SDF) in the pathophysiology of male infertility. SDF has emerged as a novel biomarker of risk stratification for patients undergoing assisted reproductive technologies. Studies have also supported the use of testicular over ejaculated sperm at the time of intracytoplasmic sperm injection, as testicular sperm may have lower SDF than ejaculated samples. The European Association of Urology Working Panel on Male Sexual and Reproductive Health provides an evidence-based consultation guide on the indications for SDF testing in male infertility and also for testicular sperm extraction (TESE) in nonazoospermic men. We present the limitations and advantages of SDF testing and a framework to ensure that it is appropriately utilised in clinical practice. Furthermore, we critically appraise the current literature advocating the use of TESE in nonazoospermic men. PATIENT SUMMARY: This article reviews the evidence supporting the use of sperm DNA fragmentation testing in the assessment of male infertility and testicular sperm extraction in nonazoospermic men.

PICSI vs. MACS for abnormal sperm DNA fragmentation ICSI cases: a prospective randomized trial

PURPOSE

To know which sperm selection technique, physiological intracytoplasmic sperm injection (PICSI) or magnetic-activated cell sorting (MACS), is better for the selection of sperm with abnormal sperm DNA fragmentation (SDF) in patients undergoing intracytoplasmic sperm injection (ICSI).

METHODS

A prospective randomized trial included 413 ICSI cases with abnormal SDF (> 20.3%) by TUNEL assay. Patients with at least 1 million total progressive motile sperm count were randomized to PICSI or MACS groups on the day of ICSI. PICSI depends on the hyaluronan binding of better SDF sperm where individual sperm was selected, while MACS selects non-apoptotic sperm population using Annexin V magnetic beads. All pre-implantation embryogenic parameters were observed and the main outcome was the ongoing pregnancy rate.

RESULTS

There were no significant differences between patients allocated to PICSI and MACS in the studied parameters including pre-implantation embryological data, implantation, clinical pregnancy, and ongoing pregnancy rates. Meanwhile, sub-analysis according to the female age has shown that female patients with less than 30 years of age in the MACS group had significantly higher good-quality blastocyst, clinical pregnancy, and ongoing pregnancy rates than the PICSI group. However, the higher implantation (p = 0.051), clinical pregnancy (p = 0.078), and ongoing pregnancy (p = 0.097) rates observed in females between 30 and 35 years of age in the PICSI group did not reach significance level.

CONCLUSIONS

PICSI and MACS are efficient techniques for sperm selection in cases with abnormal sperm DNA fragmentation. However, MACS is preferred when the females are younger than 30 years, while PICSI is preferred in older females.

CLINICAL TRIAL REGISTRATION NUMBER

NCT03398317 (retrospectively registered).

Incidence of high sperm DNA fragmentation in a targeted population of subfertile men

Sperm DNA integrity is important for fertility, however the incidence of high levels of DNA fragmentation (DNA fragmentation index (DFI) >30%) is not well described. In 2011, our clinics implemented guidelines for sperm DNA fragmentation (SDF) testing based on risk factors using the sperm chromatin structure assay (SCSA). The aim of this retrospective study is to characterise SDF and associated factors (age, semen parameters, smoking status and BMI) for sub-fertile males (n = 1082) and sperm donors (n = 234). The average DFI was 12.1 ± 9.8%. The distribution of men with low, moderate and high SDF (<15, 15-30 and >30%) was 74.8%, 19.4% and 5.8%, respectively. Men with high DFI were older (45 ± 9.5 vs 38 ± 6.7) and had lower percentage of motile sperm (38.8 ± 16.1% vs 55.3 ± 15.8%) than men with normal DFI. Over 17% of the men in the quartile with the highest age and lowest motility had a high DFI (>30%), compared to a high DFI rate of 2-4% for the other 3 quartiles. Repeat testing following lifestyle interventions was available for 29 couples where the men had high initial DFI (35 ± 9.5%). Of these men, 71.4% had a decrease of DFI into the moderate or low range. This study shows that SDF testing can be targeted based on age and sperm motility, thereby reducing unnecessary testing. Furthermore, we provide evidence that lifestyle modifications can reduce DNA fragmentation in men with high DFI.

Double-blind, randomised, placebo-controlled trial on the effect of L-carnitine and L-acetylcarnitine on sperm parameters in men with idiopathic oligoasthenozoospermia

Carnitine is essential for energy metabolism and spermatozoa maturation. Combining L-carnitine and L-acetylcarnitine with micronutrients has been investigated as a treatment for infertility in men. We evaluated the effects of a therapeutic formulation, Proxeed Plus, on sperm parameters in oligoasthenozoospermic men. This prospective, randomised, double-blind, placebo-controlled clinical trial involved 175 males (19-44 years) with idiopathic oligoasthenozoospermia who failed to impregnate their partners (12 months). Males received Proxeed Plus or placebo for 3 and 6 months. Sperm volume, progressive motility and vitality significantly (p < 0.001) improved after 6 months compared to baseline. Sperm DNA fragmentation index significantly decreased compared to baseline (p < 0.001) and the 3-month therapy (p = 0.014) in treated men. Increased seminal carnitine and α-glucosidase concentration also positively correlated with improved progressive motility. Decreased DNA fragmentation index was the good predictor of progressive sperm motility >10%, and simultaneous measurement of changes in sperm vitality and DNA fragmentation index gave the highest probability of sperm motility 10% (AUC = 0.924; 95% CI = 0.852-0.996; p < 0.001). Logistic regression analyses revealed DNA fragmentation index decrease as the only independent predictor of sperm motility 10% (OR = 1.106; p = 0.034). We have demonstrated the beneficial effects of carnitine derivatives on progressive motility, vitality and sperm DNA fragmentation. Combining metabolic and micronutritive factors is beneficial for male infertility.

Double-blind, randomised, placebo-controlled trial on the effect of L-carnitine and L-acetylcarnitine on sperm parameters in men with idiopathic oligoasthenozoospermia

Carnitine is essential for energy metabolism and spermatozoa maturation. Combining L-carnitine and L-acetylcarnitine with micronutrients has been investigated as a treatment for infertility in men. We evaluated the effects of a therapeutic formulation, Proxeed Plus, on sperm parameters in oligoasthenozoospermic men. This prospective, randomised, double-blind, placebo-controlled clinical trial involved 175 males (19-44 years) with idiopathic oligoasthenozoospermia who failed to impregnate their partners (12 months). Males received Proxeed Plus or placebo for 3 and 6 months. Sperm volume, progressive motility and vitality significantly (p < 0.001) improved after 6 months compared to baseline. Sperm DNA fragmentation index significantly decreased compared to baseline (p < 0.001) and the 3-month therapy (p = 0.014) in treated men. Increased seminal carnitine and α-glucosidase concentration also positively correlated with improved progressive motility. Decreased DNA fragmentation index was the good predictor of progressive sperm motility >10%, and simultaneous measurement of changes in sperm vitality and DNA fragmentation index gave the highest probability of sperm motility 10% (AUC = 0.924; 95% CI = 0.852-0.996; p < 0.001). Logistic regression analyses revealed DNA fragmentation index decrease as the only independent predictor of sperm motility 10% (OR = 1.106; p = 0.034). We have demonstrated the beneficial effects of carnitine derivatives on progressive motility, vitality and sperm DNA fragmentation. Combining metabolic and micronutritive factors is beneficial for male infertility.

Utility and Predictive Value of Human Standard Semen Parameters and Sperm DNA Dispersion for Fertility Potential

Because the assessment of sperm DNA fragmentation (SDF) plays a key role in male fertility, our study was designed to find the relationships between SDF and standard semen parameters. The receiver operating characteristic (ROC) curve showed that 18% SDF is a prognostic parameter for discriminating between men with normal and abnormal standard semen parameters (n = 667). Men with > 18% SDF had significantly lower quality semen, a higher prevalence of abnormal semen characteristics, and a higher odds ratio for abnormal semen parameters compared to men with ≤ 18% SDF. An ROC analysis provided predictive values for age and semen parameters to distinguish between men with SDF > 18% and men with ≤ 18% SDF. SDF was positively correlated with male age and teratozoospermia index but negatively with sperm concentration, total number of spermatozoa, sperm morphology, progressive motility, and vitality. Our study shows that 18% SDF has a predictive value for distinguishing between men with normal and abnormal semen characteristics. Men with >18% SDF have a higher risk for abnormal semen parameters, while age and obtained semen parameters have a predictive value for SDF. There is a relationship between SDF and conventional sperm characteristics, and thus, SDF can be incorporated into male fertility assessment.

Sperm DNA fragmentation valued by SCSA and its correlation with conventional sperm parameters in male partner of recurrent spontaneous abortion couple

The objective of this study is to evaluate the predictive value of sperm DNA fragmentation Index (DFI) in unexplained recurrent spontaneous abortion (RSA) and to investigate its correlation with conventional sperm parameters. Besides, we aimed to reveal the necessity of establishing a DFI clinical threshold of each laboratory for the prognostic diagnosis of RSA and establish our own DFI threshold. Semen samples were collected from male partners of RSA patients (n = 139) and healthy recent fathers (control, n = 200). DFI was tested using SCSA and conventional semen analysis was performed using an automatic semen analyzer. The DFI value and distribution were compared between the two groups using corresponding statistical software. The diagnostic threshold value was established by ROC curve. The correlation between DFI and the conventional semen parameters of the 139 cases was further analyzed using Student's t test and Mann-Whitney U test. Our result showed that DFI was significantly higher in RSA patients compared with normal donor controls. We established our own DFI threshold at 13.59%. There was only a weak partial correlation between DFI values and conventional sperm analysis parameters. Our present study suggested that DFI might be used as a valuable predictor for RSA independent of conventional sperm parameters. Additionally, we recommend that each laboratory should establish its own clinical DFI threshold for more precise prediction of RSA and we recommend that sperm DNA fragmentation test should be included in complete sperm quality assessment in addition to conventional semen analysis for RSA male partners.

Sperm DNA fragmentation and recurrent pregnancy loss: a systematic review and meta-analysis

OBJECTIVE

To investigate the rate of sperm DNA fragmentation in male partners of women with recurrent pregnancy loss and fertile control women.

DESIGN

Systematic review and meta-analysis.

SETTING

Not applicable.

PATIENT(S)

A total of 579 male partners of women with recurrent pregnancy loss and 434 male partners fertile control women.

INTERVENTION(S)

Prospective studies were identified through a Pubmed search. Recurrent pregnancy loss was defined as two or more previous pregnancy losses. Fertile control women had a history of a live birth or ongoing pregnancy.

MAIN OUTCOME MEASURE(S)

The primary outcome was the rate of sperm DNA fragmentation. The summary measures were reported as mean difference with 95% confidence interval (CI).

RESULT(S)

Fifteen prospective studies were included in a qualitative review. Pooled data from 13 studies with sufficient data for meta-analysis suggest that male partners of women with a history of recurrent pregnancy loss have a significantly higher rate of sperm DNA fragmentation compared to the partners of fertile control women: mean difference 11.91, 95% CI 4.97-18.86.

CONCLUSION(S)

These findings support an association between sperm DNA fragmentation and recurrent pregnancy loss. However, given the significant heterogeneity between studies and lack of prospective pregnancy outcome data, further large prospective studies are needed.

Complete urological evaluation including sperm DNA fragmentation in male systemic lupus erythematosus patients

Objective

To evaluate sperm DNA fragmentation analysis in non-azoospermic male systemic lupus erythematosus (SLE) patients.

Methods

Twenty-eight consecutive male SLE patients (American College of Rheumatology criteria) and 34 healthy controls were evaluated for demographic/exposures data, urological evaluation, hormone profile and sperm analysis (including sperm DNA fragmentation). Clinical features, disease activity/damage scores and treatment were also evaluated.

Results

The median age (33 (20–52) vs. 36.5 (25–54) years, P = 0.329) and frequency of varicocele (25% vs. 32%, P = 0.183) were similar in SLE patients and healthy controls. Sperm DNA fragmentation showed significantly higher levels of cells class III (44 (9–88) vs. 16.5 (0–80)%, P = 0.001) and cell class IV (10.5 (3–86) vs. 7 (0–36)%, P = 0.039) in SLE. The sperm DNA fragmentation index was also significantly higher in SLE patients (62 (31–97) vs. 25.5 (0–100)%, P < 0.001). Conventional sperm parameters (including sperm count, motility and morphology) were similar in both groups. In SLE patients no correlations were observed between sperm DNA fragmentation index and age, disease duration, Systemic Lupus Erythematosus Disease Activity Index 2000 and Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index scores, and cumulative dose of prednisone, hydroxychloroquine, intravenous cyclophosphamide, methotrexate, azathioprine and mycophenolate mofetil ( P > 0.05). Further analysis of SLE patients treated with and without intravenous cyclophosphamide showed that total sperm motility was significantly lower in the former group (64% (15–83) vs. 72% (57–86), P = 0.024). The sperm DNA fragmentation index was alike in both groups (52.5 (31–95) vs. 67.5 (34–97)%, P = 0.185).

Conclusions

To our knowledge, this is the first demonstration that male non-azoospermic SLE patients have increased sperm DNA fragmentation without evident gonadal dysfunction. Intravenous cyclophosphamide does not seem to be a major determinant for this abnormality. Future prospective study is necessary to determine the impact of this alteration in these patients' fertility.

Lifestyle and fertility: the influence of stress and quality of life on male fertility

BACKGROUND

Male infertility is a widespread condition among couples. In about 50% of cases, couple infertility is attributable to the male partner, mainly due to a failure in spermatogenesis. In recent times, the crucial role that modifiable lifestyle factors play in the development of infertility have generated a growing interest in this field of study, i.e. aging, psychological stress, nutrition, physical activity, caffeine, high scrotal temperature, hot water, mobile telephone use. Several studies have investigated associations between semen quality and the presence of lifestyle stressors i.e. occupational, life events (war, earthquake, etc.) or couple infertility; overall, these studies provide evidence that semen quality is impaired by psychological stress. In this review, we will discuss the impact of quality of life (modifiable lifestyle factors) and psychological stress on male fertility. In addition, the role that increased scrotal temperature along with inappropriate nutritional and physical exercise attitudes exert on male fertility will be presented.

CONCLUSION

The decline of male fertility, particularly associated with advancing age, incorrect lifestyles and environmental factors plays an important role on natality, and its consequences on the future on human population makes this an important public health issue in this century. Thus, modification of lifestyle through a structured program of educational, environmental, nutritional/physical exercise and psychological support, combined with the use of nutraceutical antioxidants can prevent infertility and therefore, may help couples to obtain better quality of life and improved possibility to conceive spontaneously or optimize their chances of conception.

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.