Effect of an abnormal sperm chromatin structural assay (SCSA) on pregnancy outcome following (IVF) with ICSI in previous IVF failures

Semen's parameters after varicocelectomy surgery with mast cell stabilizers treatment in infertile varicocele patients: Randomized clinical trial study

Background and Aims

Varicocele is one of the most common causes of male infertility in which testicular function is progressively damaged. This study aims to investigate the effect of varicocelectomy and mast cell stabilizers on reducing sperm DNA fragmentation in infertile patients with varicocele.

Methods

In this randomized clinical trial, after obtaining ethical approval and informed consent, infertile patients with varicocele were randomly assigned to three groups: varicocelectomy, 1 mg ketotifen, and varicocelectomy plus with 1 mg ketotifen for 3-month follow-up. Semen analysis and estimation of DNA fragmentation index (DFI) were obtained from all people in the studied time periods.

Results

In this study, 420 infertile patients with varicocele were included with an average age of 31.6 years. The results showed that sperm morphology, sperm motility, sperm count, and sperm DFI had significant differences after the intervention (p < 0.05). Also, the results of semen analysis for each group showed that there was a significant improvement in sperm morphology, motility, count, and DFI index of infertile people with varicocele after the intervention (p < 0.05). But the difference was statistically higher in the varicocelectomy plus with 1 mg ketotifen group than in the other groups (p < 0.01).

Conclusion

The evidence and results of this study showed that the use of varicocelectomy plus ketotifen in infertile people with varicocele was more effective in improving Semen parameters than the use of mast cell stabilizers or varicocelectomy alone.

Sperm DNA fragmentation negatively influences the cumulative live birth rate in the intracytoplasmic sperm injection cycles of couples with unexplained infertility

Objective: This study aimed to determine the effect of sperm DNA fragmentation (SDF) on the cumulative live birth rate (CLBR) in intracytoplasmic sperm injection (ICSI) cycles in couples with unexplained infertility.Methods: We conducted a prospective study of 145 couples who underwent ICSI cycles for unexplained infertility. Based on the SDF rate, patients were categorized into a low SDF group (SDF ≤30%, n=97) and a high SDF group (SDF >30%, n=48). SDF was assessed using the acridine orange test on density gradient centrifugation prepared samples. The CLBR was calculated as the first live birth event per woman per egg collection over 2 years.Results: The high SDF group (SDF >30%) showed a significantly lower CLBR (p<0.05) and a significantly higher miscarriage rate (p<0.05) than the low SDF group (SDF ≤30%). No significant difference was observed in the implantation and cumulative pregnancy rates between the two SDF groups. The total number of embryo transfers was stratified further into fresh and frozen embryo transfers. In the fresh embryo transfers, there were significant differences in the implantation rates, clinical pregnancy rates, and live birth rates (p<0.05) between the low SDF and high SDF groups. However, in the frozen embryo transfers, there were no significant differences in clinical outcomes between the two groups. In the multivariable logistic regression analysis, SDF was a predictor of CLBR (p<0.05) when adjusted for possible confounding factors.Conclusion: High SDF was associated with a lower CLBR and a higher miscarriage rate in the ICSI cycles of couples with unexplained infertility.

Can sperm quality influence embryo development and its ploidy? Analysis of 811 blastocysts obtained from different sperm sources

The aim of our study was to evaluate the correlation between sperm quality and ploidy status of the derived blastocysts. We performed a retrospective analysis on a restricted pool of patients enrolling only those who had no female factors. Male patients with genetic factors affecting spermatogenesis were also excluded. We chose a maternal age ≤38 years to decrease the female factor, therefore the male factor was the main component of sterility. We divided the patients in four groups based on semen quality and comparing fertilization, pregnancy and euploidy rates above all. In total, 201 intracytoplasmic sperm injection (ICSI) cycles were enrolled in the study. Cycles were divided into four groups, according to semen source: normal semen, oligoasthenoteratozoospermia (OAT), cryptospermia or non-obstructive azoospermia (NOA). An extremely statistically lower fertilization rate was found in NOA patients. Unexpectedly, no differences were detected in blastocyst formation, euploidy, aneuploidy and mosaicism rates among the four groups. Interestingly, we also found a higher abortion rate comparing NOA to normal semen with an odds ratio of 4.67. In our study no statistically significant differences among the analyzed groups were found, showing little or no effect at all using spermatozoa from different semen sources or quality. This may be linked to the oocyte competence of fixing sperm DNA damage and it could be hypothesized that only sperm with a good rate of DNA integrity are able to fertilize the oocyte, explaining why poor quality semen is reflected in a low fertilization rate without effect on ploidy.

Role of female age in regulating the effect of sperm DNA fragmentation on the live birth rates in intracytoplasmic sperm injection cycles with own and donor oocytes

Background:

Sperm DNA integrity assessment has been progressively used as an unfettered measure of sperm as it proffers more prognostic and diagnostic information than routine semen analysis. The contentious effect of sperm DNA fragmentation (SDF) on clinical outcomes can be attributed to female factors such as age, oocyte quality and ovarian reserve.

Aims:

The study is mainly aimed to know the influence of SDF on the live birth rates in intracytoplasmic sperm injection (ICSI) cycles with own and donor oocytes. Second, to know the role of female age in regulating the effect of SDF on the live birth rates in ICSI cycles with own and donor oocytes.

Setting and Design:

A prospective cohort study was done at our tertiary care centre attached to the reproductive medicine unit in medical college.

Materials and Methods:

The study included 356 patients who underwent first ICSI cycles either with own or donor-oocytes along with day 5 fresh embryo transfers only. The main outcome measures were live birth rates and miscarriage rates.

Statistical Analysis Used:

Chi-squared test was used to compare the categorical variables between the groups. The receiver operating characteristic curve was developed to correlate the female age with the live birth rate.

Results:

A significant decrease in the live birth rates (42.85% vs. 26.15%, P = 0.023) and an increase in the miscarriage rates (12.30% vs. 34.61%, P = 0.013) were observed in the high-SDF group ICSI cycles of own-oocyte patients. However, there was no significant difference in the live birth rates and miscarriage rates in the low- and high-SDF groups of donor oocyte ICSI cycle patients (P > 0.05). The own-oocyte ICSI cycle patients were further stratified based on the female age. In the female age group ≤30 years there was no significant difference in the live birth and miscarriage rates (P > 0.05) similar to donor oocyte ICSI cycles. Whereas, there was a significant difference in the live birth rates in the females of age >30 years (13.79% vs. 34.37%, P = 0.040).

Conclusion:

In conclusion, high-SDF has a negative influence on the live birth rates and a positive influence on the miscarriage rates in patients with own-oocyte ICSI cycles. A similar influence was not observed in patients with donor-oocyte ICSI cycles and in young female patients (age ≤30 years) with own-oocyte ICSI cycles.

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.

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.

Sperm DNA fragmentation index influences assisted reproductive technology outcome: A systematic review and meta-analysis combined with a retrospective cohort study

Studies have explored the influence of DNA damage in assisted reproductive technology (ART), but the outcome remains controversial. To determine whether sperm DNA fragmentation index (DFI) has any effect on ART outcomes, we collected detailed data regarding 1,333 IVF cycles performed at our centre, and the data of our retrospective cohort study were extracted for this meta-analysis. We searched PubMed, Web of Science, EMBASE and Google Scholar and performed a systemic review and meta-analysis. Primary meta-analysis of 10 studies comprising 1,785 couples showed that live birth rate was no significantly different between low-DFI group and high-DFI group (p > 0.05). Secondary meta-analysis of 25 studies comprising 3,992 couples showed a higher miscarriage rate in high-DFI group than in low-DFI group (RR=1.57 [1.18, 2.09], p < 0.01). Meta-analysis of eight studies comprising 17,879 embryos revealed a lower good-quality embryo rate (RR=0.65 [0.62, 0.68], p < 0.01). Meta-analysis of 23 studies comprising 6,771 cycles showed that the high-DFI group had a lower clinical pregnancy rate than low-DFI group (RR=0.85 [0.75, 0.96], p < 0.01). Heterogeneity of included studies weakened our conclusions. Our study showed that DFI has adverse effects on ART outcome. More well-designed studies exploring the association between DFI and ART outcome are desired.

What should be done for men with sperm DNA fragmentation?

In an age when a small quantity of sperm can lead to pregnancy through in vitro fertilization or intracytoplasmic sperm injection, selecting healthy sperm is important. Sperm DNA fragmentation (SDF) is known to be higher in infertile men. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) and the alkaline comet test are SDF tests that directly measure DNA damage and have shown closer correlations with assisted reproduction results than indirect tools such as the sperm chromatin structure assay or the sperm chromatic dispersion test. It is difficult; however, to endorse a single test as the best test overall; instead, it is best to select a testing method based on each patient's clinical condition and goals. In a couple struggling with infertility, if the male partner has a high level of SDF, he should aim to decrease SDF through lifestyle modifications, antioxidant treatment, and ensuring an appropriate duration of abstinence, and physicians need to treat the underlying diseases of such patients. If sperm DNA damage continues despite the patient's and physician's efforts, other methods, such as micromanipulation-based sperm selection or testicular sperm extraction, should be used to select healthy sperm with nuclear DNA integrity.

RNF8 and SCML2 cooperate to regulate ubiquitination and H3K27 acetylation for escape gene activation on the sex chromosomes

The sex chromosomes are enriched with germline genes that are activated during the late stages of spermatogenesis. Due to meiotic sex chromosome inactivation (MSCI), these sex chromosome-linked genes must escape silencing for activation in spermatids, thereby ensuring their functions for male reproduction. RNF8, a DNA damage response protein, and SCML2, a germline-specific Polycomb protein, are two major, known regulators of this process. Here, we show that RNF8 and SCML2 cooperate to regulate ubiquitination during meiosis, an early step to establish active histone modifications for subsequent gene activation. Double mutants of Rnf8 and Scml2 revealed that RNF8-dependent monoubiquitination of histone H2A at Lysine 119 (H2AK119ub) is deubiquitinated by SCML2, demonstrating interplay between RNF8 and SCML2 in ubiquitin regulation. Additionally, we identify distinct functions of RNF8 and SCML2 in the regulation of ubiquitination: SCML2 deubiquitinates RNF8-independent H2AK119ub but does not deubiquitinate RNF8-dependent polyubiquitination. RNF8-dependent polyubiquitination is required for the establishment of H3K27 acetylation, a marker of active enhancers, while persistent H2AK119ub inhibits establishment of H3K27 acetylation. Following the deposition of H3K27 acetylation, H3K4 dimethylation is established as an active mark on poised promoters. Together, we propose a model whereby regulation of ubiquitin leads to the organization of poised enhancers and promoters during meiosis, which induce subsequent gene activation from the otherwise silent sex chromosomes in postmeiotic spermatids.

Effect of varicocelectomy and/or mast cells stabilizer on sperm DNA fragmentation in infertile patients with varicocele

This study aimed to assess the effect of varicocelectomy and/or mast cells (MCs) stabilizer on sperm DNA fragmentation in infertile men with varicocele (Vx). Overall, 120 infertile patients were randomized to three equal treatment arms; patients that underwent varicocelectomy, patients on 1 mg ketotifen twice daily for three months, and patients that underwent varicocelectomy followed with 1 mg ketotifen twice daily for three months. These patients were subjected to history taking, clinical examination, semen analysis, and estimation of sperm DNA fragmentation index (DFI). After 3 months, all investigated groups showed significant improvement regarding the mean total sperm count, sperm concentration, total sperm motility, and sperm normal forms percentage compared with the pre-treatment data. As well, the mean sperm DFI was significantly improved compared with the pre-treatment data; in men that underwent varicocelectomy (34.6% vs. 28.3%), in men on MC stabilizer only (33.4% vs. 27.8%), and in men that underwent varicocelectomy followed by MC stabilizer (34.3% vs. 25.1%). Sperm DFI improvement percentages showed the highest improvement in men that underwent varicocelectomy followed with MC stabilizer compared with the other two groups (26.8% vs. 18.2%, 16.8%). Sperm DFI improvement percentages showed significant increases in the infertile patients with Vx grade III compared to Vx grade II in all investigated groups. It is concluded that in infertile men associated with Vx and high sperm DFI, surgical repair followed with MCs stabilizer significantly improve sperm DFI compared with either surgical repair or MCs stabilizer alone.

ICSI significantly improved the pregnancy rate of patients with a high sperm DNA fragmentation index

Objective

Correlations between semen parameters and sperm DNA fragmentation index (DFI) were investigated to identify characteristics of sperm without DNA damage that could be used in selecting sperm for intracytoplasmic sperm injection (ICSI). Pregnancy outcomes were compared to determine whether in vitro fertilization (IVF) or ICSI is a better choice for patients who have sperm with a high-DFI.

Methods

Semen analysis was carried out in 388 patients who visited our IVF center for the first time to investigate correlations between sperm DFI and semen parameters. In addition, 1,102 IVF cycles in 867 patients were carried out in the present study; 921 cycles in the low-DFI group (DFI <30%) and 181 cycles in the high-DFI group (DFI ≥30%). Both the low- and high-DFI groups were subdivided into IVF and ICSI cycle groups.

Results

Sperm DFI showed significant inverse correlations with sperm motility (r=−0.435, p<0.001) and morphology (r=−0.153, p<0.05). Sperm DFI also showed significant correlations with rapid motility (r=−0.436, p<0.001), and the kinetic parameters of average-path velocity (r=−0.403) and linearity (r=−0.412). Although there was no significant difference in the pregnancy rates between IVF (48.6%) and ICSI (44.8%) in the low-DFI group, the pregnancy rate of ICSI cycles (44.8%, p<0.05) was significantly higher than IVF cycles (25.0%) in the high-DFI group. No significant difference was observed in the abortion rates between the low-DFI (52 of 921, 5.6%) and high-DFI groups (7 of 181, 3.8%).

Conclusion

ICSI is a better choice than IVF for improving the pregnancy outcomes of patients who have sperm with a high DFI.

A systematic review and meta-analysis to determine the effect of sperm DNA damage on in vitro fertilization and intracytoplasmic sperm injection outcome

Sperm DNA damage is prevalent among infertile men and is known to influence natural reproduction. However, the impact of sperm DNA damage on assisted reproduction outcomes remains controversial. Here, we conducted a meta-analysis of studies on sperm DNA damage (assessed by SCSA, TUNEL, SCD, or Comet assay) and clinical pregnancy after IVF and/or ICSI treatment from MEDLINE, EMBASE, and PUBMED database searches for this analysis. We identified 41 articles (with a total of 56 studies) including 16 IVF studies, 24 ICSI studies, and 16 mixed (IVF + ICSI) studies. These studies measured DNA damage (by one of four assays: 23 SCSA, 18 TUNEL, 8 SCD, and 7 Comet) and included a total of 8068 treatment cycles (3734 IVF, 2282 ICSI, and 2052 mixed IVF + ICSI). The combined OR of 1.68 (95% CI: 1.49–1.89; P < 0.0001) indicates that sperm DNA damage affects clinical pregnancy following IVF and/or ICSI treatment. In addition, the combined OR estimates of IVF (16 estimates, OR = 1.65; 95% CI: 1.34–2.04; P < 0.0001), ICSI (24 estimates, OR = 1.31; 95% CI: 1.08–1.59; P = 0.0068), and mixed IVF + ICSI studies (16 estimates, OR = 2.37; 95% CI: 1.89–2.97; P < 0.0001) were also statistically significant. There is sufficient evidence in the existing literature suggesting that sperm DNA damage has a negative effect on clinical pregnancy following IVF and/or ICSI treatment.

Measuring Sperm DNA Fragmentation and Clinical Outcomes of Medically Assisted Reproduction: A Systematic Review and Meta-Analysis

Sperm DNA fragmentation has been associated with reduced fertilization rates, embryo quality, pregnancy rates and increased miscarriage rates. Various methods exist to test sperm DNA fragmentation such as the sperm chromatin structure assay (SCSA), the sperm chromatin dispersion (SCD) test, the terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick end labelling (TUNEL) assay and the single cell gel electrophoresis (Comet) assay. We performed a systematic review and meta-analysis to assess the value of measuring sperm DNA fragmentation in predicting chance of ongoing pregnancy with IVF or ICSI. Out of 658 unique studies, 30 had extractable data and were thus included in the meta-analysis. Overall, the sperm DNA fragmentation tests had a reasonable to good sensitivity. A wide variety of other factors may also affect the IVF/ICSI outcome, reflected by limited to very low specificity. The constructed hierarchical summary receiver operating characteristic (HSROC) curve indicated a fair discriminatory capacity of the TUNEL assay (area under the curve (AUC) of 0.71; 95% CI 0.66 to 0.74) and Comet assay (AUC of 0.73; 95% CI 0.19 to 0.97). The SCSA and the SCD test had poor predictive capacity. Importantly, for the TUNEL assay, SCD test and Comet assay, meta-regression showed no differences in predictive value between IVF and ICSI. For the SCSA meta-regression indicated the predictive values for IVF and ICSI were different. The present review suggests that current sperm DNA fragmentation tests have limited capacity to predict the chance of pregnancy in the context of MAR. Furthermore, sperm DNA fragmentation tests have little or no difference in predictive value between IVF and ICSI. At this moment, there is insufficient evidence to recommend the routine use of sperm DNA fragmentation tests in couples undergoing MAR both for the prediction of pregnancy and for the choice of treatment. Given the significant limitations of the evidence and the methodological weakness and design of the included studies, we do urge for further research on the predictive value of sperm DNA fragmentation for the chance of pregnancy after MAR, also in comparison with other predictors of pregnancy after MAR.

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.

Engaging practicing gynecologists in the management of infertile men

In the modern era, contemporary management of male infertility has undergone groundbreaking changes with the introduction of new concepts, advanced testing, and therapeutic interventions. As practicing gynecologists are often the first physicians who encounter an infertile couple, it is essential that these clinicians are continuously updated about the new pearls and pitfalls of male infertility management. Semen analysis is commonly ordered by gynecologists. In 2010, the WHO released new cutoff reference values for the semen parameters adopting novel methodology, which has incited much debate. Reference values have been lowered in comparison with previous standards, with a direct clinical implication in decision-making strategies. Specialized sperm-function tests, such as sperm oxidative stress and sperm chromatin integrity assessments, became clinically available, thus offering an opportunity to better understand sperm dysfunctions concealed during routine semen analysis. Furthermore, the initial counseling of azoospermic men by an andrologically well educated gynecologist may alleviate the misconception and distress surrounding the false belief of sterility, and will clarify the available options of percutaneous and microsurgical sperm-retrieval techniques and assisted conception outcome. Regarding varicocele, which is commonly seen in infertile males, it is now clear that the best treatment option for infertile men with clinical varicocele is the microsurgical vein ligation. Natural conception is significantly improved after varicocelectomy, and recent data suggest that such treatment optimizes reproductive outcome of couples undergoing ICSI or micro-TESE sperm retrieval. Lastly, new therapeutic interventions, including oral antioxidant therapy and lifestyle modifications, have gained increasing attention, as they aid in alleviating male infertility.

The effect of sperm DNA fragmentation on live birth rate after IVF or ICSI: a systematic review and meta-analysis

A systematic review and meta-analysis was conducted to evaluate the relationship between the extent of sperm DNA damage and live birth rate (LBR) per couple and the influence of the method of fertilization on treatment outcome. Searches were conducted on MEDLINE, EMBASE and Cochrane Library. Six studies were eligible for inclusion in the meta-analysis. Overall, LBR increased signficantly in couples with low sperm DNA fragmentation compared with those with high sperm DNA fragmentation (RR 1.17, 95% CI 1.07 to 1.28; P = 0.0005). After IVF and intracytoplasmic sperm injection (ICSI), men with low sperm DNA fragmentation had significantly higher LBR (RR 1.27, 95% CI 1.05 to 1.52; P = 0.01) and (RR 1.11, 95% CI 1.00 to 1.23, P = 0.04), respectively. A sensitivity analysis showed no statistically significant difference in LBR between low and high sperm DNA fragmentation when ICSI treatment was used (RR 1.08, 95% CI 0.39 to 2.96; P = 0.88). High sperm DNA fragmentation in couples undergoing assisted reproduction techniques is associated with lower LBR. Well-designed randomized studies are required to assess the role of ICSI over IVF in the treatment of men with high sperm DNA fragmentation.

Paternal influence of sperm DNA integrity on early embryonic development

STUDY QUESTION

Does sperm DNA damage affect early embryonic development?

SUMMARY ANSWER

Increased sperm DNA damage adversely affects embryo quality starting at Day 2 of early embryonic development and continuing after embryo transfer, resulting in reduced implantation rates and pregnancy outcomes.

WHAT IS KNOWN ALREADY

Abnormalities in the sperm DNA in the form of single and double strand breaks can be assessed by an alkaline Comet assay. Some prior studies have shown a strong paternal effect of sperm DNA damage on IVF outcome, including reduced fertilization, reduced embryo quality and cleavage rates, reduced numbers of embryos developing into blastocysts, increased percentage of embryos undergoing developmental arrest, and reduced implantation and pregnancy rates.

STUDY DESIGN, SIZE, DURATION

A cross-sectional study of 215 men from infertile couples undergoing assisted reproduction techniques at the University of Utah Center for Reproductive Medicine.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Sperm from men undergoing ART were analyzed for DNA damage using an alkaline Comet assay and classified into three groups: 'low damage' (0-30%), 'intermediate damage' (31-70%) and 'high damage' (71-100%). The cause of couples' infertility was categorized into one of the three types (male, female or unexplained). Each embryo was categorized as 'good', 'fair' or 'poor' quality, based on the number and grade of blastomeres. The influence of sperm DNA damage on early embryonic development was observed and classified into four stages: peri-fertilization effect (fertilization rate), early paternal effect (embryonic days 1-2), late paternal effect (embryonic days 3-5) and implantation stage effect.

MAIN RESULTS AND THE ROLE OF CHANCE

The paternal effect of sperm DNA damage was observed at each stage of early embryonic development. The peri-fertilization effect was higher in oocytes from patients with female infertility (20.85%) compared with male (8.22%; P < 0.001) and unexplained (7.30%; P < 0.001) infertility factors. In both the early and late paternal effect stages, the low DNA damage group had a higher percentage of good quality embryos (P < 0.05) and lower percentage of poor quality embryos (P < 0.05) compared with the high DNA damage group. Implantation was lower in the high DNA damage (33.33%) compared with intermediate DNA damage (55.26%; P < 0.001) and low DNA damage (65.00%; P < 0.001) groups. The implantation rate was higher following blastocyst transfer (58.33%), when compared with early stage blastocyst (53.85%; P = 0.554) and cavitating morula transfers (34.40%; P < 0.001). Implantation was higher when the female partner age was ≤35 years when compared with >35 year age group (52.75 versus 35.44%; P = 0.008).

LIMITATIONS, REASONS FOR CAUTION

A potential limitation of this study is that it is cross-sectional. Generally in such studies more than one variable could affect the outcome. Analyzing sperm is one part of the equation but a number of environmental and female factors also have the potential to influence embryo development and implantation. Furthermore, the selection of morphologically normal and physiologically motile sperm may result in isolation of sperm with reduced DNA damage. Therefore, selecting the best available sperm for ICSI may lead to experimental bias, as the selected sperm do not represent the overall sperm population in which the DNA damage is measured. Similar studies on selected sperm and with a larger sample size are now required.

WIDER IMPLICATIONS OF THE FINDINGS

The paternal influence of damaged chromatin is more prominent after zygotic transcriptional activation. A prolonged paternal effect on the developing embryo may be due to the active repair mechanism present in oocytes that tends to overcome the damaged paternal chromatin. The probability of eliminating an embryo fertilized by a sperm with damaged DNA is higher at the blastocyst stage than the cleavage stage; therefore blastocyst transfer could be recommended for better implantation success. Finally, we recommend ICSI treatment for patients with a higher percentage of sperm with DNA damage as well as additional studies with a larger sample size aimed at assessing DNA damage analysis as a diagnostic tool for IVF.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by the University of Utah internal funds. The authors declare no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Whether sperm deoxyribonucleic acid fragmentation has an effect on pregnancy and miscarriage after in vitro fertilization/intracytoplasmic sperm injection: a systematic review and meta-analysis

OBJECTIVE

To examine whether sperm DNA fragmentation has an effect on pregnancy and miscarriage after IVF and/or intracytoplasmic sperm injection (ICSI).

DESIGN

Systematic review and meta-analysis.

SETTING

University-affiliated teaching hospital.

PATIENT(S)

Infertility patient(s).

INTERVENTION(S)

An exhaustive electronic literature search was conducted on MEDLINE, Google Scholar, and the Cochrane Library, from database inception to October 2013. We included clinical trials that examined the influence of sperm DNA damage on pregnancy and miscarriage of IVF/ICSI.

MAIN OUTCOME MEASURE(S)

The outcomes of interest were pregnancy rate and miscarriage rate.

RESULT(S)

In the analysis of pregnancy, 16 cohort studies (3,106 couples) were included. Of these, 14 studies (2,756 couples, 965 pregnancies) that also mentioned miscarriage were identified in the analysis of miscarriage. Meta-analysis showed that high-level sperm DNA fragmentation has a detrimental effect on outcome of IVF/ICSI, with decreased pregnancy rate and increased miscarriage rate. The stratified analysis by type of procedure (IVF vs. ICSI) indicated that high sperm DNA damage was related to lower pregnancy rates in IVF but not in ICSI cycles, whereas it was associated with higher miscarriage rates in both IVF and ICSI cycles.

CONCLUSION(S)

The results indicate that assays detecting sperm DNA damage should be recommended to those suffering from recurrent failure to achieve pregnancy. Selection of sperm without DNA damage for use may improve the clinical outcome of ART. The data also provide a rationale for conducting further research aimed at evaluating the underlying mechanism(s) responsible for the detrimental effect of high sperm DNA fragmentation and the potential therapy.

A translational medicine appraisal of specialized andrology testing in unexplained male infertility

The diagnostic and prognostic validity of sperm function biomarkers is particularly relevant for males with unexplained infertility in which routine semen analysis fails to detect subcellular sperm dysfunctions. In this general review, we examine the role and significance of specialized andrology laboratory tests from past to present and provide a glance toward the future. We concluded that the assessment of sperm DNA damage and oxidative stress provide a relatively independent measure of fertility that yields diagnostic and prognostic information complementary to, but distinct and more significant than, standard sperm parameters. Since none of the available methods for such testing have been fully translated, further research is necessary to evaluate their cost-effectiveness when applied in large scale to daily medical practice. Application of translational medicine concepts would also be useful to accelerate the clinical application of recent discoveries in the fields of genomics, proteomics and metabolomics.

Diagnostic accuracy of sperm chromatin dispersion test to evaluate sperm deoxyribonucleic acid damage in men with unexplained infertility

OBJECTIVE

To compare the sperm chromatin dispersion (SCD) test and the terminal uridine nick-end labeling (TUNEL) assay for assessment of sperm DNA damage.

DESIGN

Prospective comparative experimental study.

SETTING

Andrology laboratory.

PATIENT(S)

Twenty subfertile men with unexplained infertility.

INTERVENTION(S)

Sperm DNA damage was determined in the same semen samples using the TUNEL assay with fluorescence microscopy and the SCD test with bright-field microscopy.

MAIN OUTCOME MEASURE(S)

Correlation coefficient and receiver operating characteristic analysis outcomes. The TUNEL assay was used as the reference standard to identify optimal cutoff points for assessing DNA damage by SCD.

RESULT(S)

The SCD test detected a significantly higher proportion of sperm with damaged DNA (20.6% ± 14.0%) than the TUNEL assay (11.5% ± 7.3%). Spearman's rank correlation showed that the methods were not comparable (r = 0.29). Receiver operating characteristic analysis revealed that 15% was the best SCD cutoff point to classify patients within the same levels of DNA fragmentation, normal or abnormal, as determined by the TUNEL assay, with an accuracy of 69%.

CONCLUSION(S)

The SCD test is more sensitive than the TUNEL assay for the assessment of DNA damage in men with unexplained infertility. Although the methods are poorly correlated, SCD may discriminate men with normal and abnormal sperm DNA damage with moderate accuracy when compared with TUNEL. It is important to distinguish between the methods because they differently evaluate sperm DNA damage.

Unexplained male infertility: diagnosis and management

Unexplained male infertility is a diagnosis reserved for men in whom routine semen analyses results are within normal values and physical as well as endocrine abnormalities were ruled out. In addition to erectile problems and coital factors, immunologic causes and sperm dysfunction may contribute to such condition. New etiologies of unexplained male infertility include low level leukocytospermia and mitochondrial DNA polymerase gene polymorphism. Contemporary andrology may reveal cellular and sub-cellular sperm dysfunctions which may explain subfertility in such cases, thus aiding the clinician to direct the further work-up, diagnosis and counseling of the infertile male. The objective of this article is to highlight the concept of unexplained male infertility and focuses on the diagnosis and treatment of this condition in the era of modern andrology and assisted reproductive techniques. Extensive literature review was performed using the search engines: Pubmed, Science-direct, Ovid and Scopus.

Quality of human spermatozoa: relationship between high-magnification sperm morphology and DNA integrity

The aim of this work is to establish the relationship between the morphology of Intracytoplasmic Morphologically Selected Sperm Injection (IMSI)-selected spermatozoa and their DNA integrity. The 45 ejaculates were randomly distributed into three treatment groups: normozoospermic, oligoasthenozoospermic and oligoasthenotheratozoospermic samples. The evaluation of DNA integrity was performed using the sperm chromatin dispersion test. It was established that DNA integrity of spermatozoa is strongly dependent on ejaculate quality (P < 0.05). The count of spermatozoa with nonfragmented DNA in normozoospermic samples was high and independent from IMSI-morphological classes (Class 1 versus Class 3, respectively) (P > 0.1). With decreased ejaculate quality, the percentage of spermatozoa with nonfragmented DNA decreased significantly (P < 0.05) independent from morphological class. Nevertheless, the rate of IMSI-selected spermatozoa with fragmented DNA within of Class 1 in normozoospermic (Group 1), in oligoasthenozoospermic (Group 2) and in oligoasthenotheratozoospermic (Group 3) samples was 21.1%, 31.8% and 54.1%, respectively. In conclusion, there is a direct relationship between morphological parameters of spermatozoa and their DNA integrity. However, the IMSI technique alone is not enough for the selection of spermatozoa with intact nuclei.

The clinical utility of sperm DNA integrity testing: a guideline

Sperm DNA damage is more common in infertile men and may contribute to poor reproductive performance. However, current methods for assessing sperm DNA integrity do not reliably predict treatment outcomes and cannot be recommended routinely for clinical use.

Clinical value of DNA fragmentation evaluation tests under ART treatments

Male reproductive health has been under scrutiny recently. Many studies in the literature have concluded that semen quality is declining and that the incidence of testicular cancers is increasing. The reason for this change has been attributed to damage in sperm chromatin. During in vivo reproduction, the natural selection process ensures that only a spermatozoon with normal genomic material can fertilize an oocyte. However, the assisted reproduction technique (ART) is our selection process, leading to the possibility that abnormal spermatozoa could be used to fertilize an oocyte. We could avoid this by quantifying the amount and type of genomic damage in sperm using well-accepted laboratory methods. The sperm deoxyribonucleic acid (DNA) integrity is important for success of natural or assisted fertilization as well as normal development of the embryo, fetus and child. Intra cytoplasmic sperm injection (ICSI) is bypassing natural sperm selection mechanisms, which increases the risk of transmitting damaged DNA. The significance of required investigations and multiple techniques is that they could evaluate DNA defects in human spermatozoa. The ability of these techniques to accurately estimate sperm DNA damage depends on many technical and biological aspects. The aim of this review is to evaluate the most commonly used methods.

The effect of sperm DNA fragmentation on miscarriage rates: a systematic review and meta-analysis

STUDY QUESTION

Is there an association between high levels of sperm DNA damage and miscarriage?

SUMMARY ANSWER

Miscarriage rates are positively correlated with sperm DNA damage levels.

WHAT IS KNOWN ALREADY

Most ejaculates contain a subpopulation of sperm with DNA damage, also referred to as DNA fragmentation, in the form of double or single-strand breaks which have been induced in the DNA prior to or following ejaculation. This DNA damage may be particularly elevated in some subfertile men, hence several studies have examined the link between sperm DNA damage levels and conception and miscarriage rates.

STUDY DESIGN, SIZE, DURATION

A systematic review and meta-analysis of studies which examined the effect of sperm DNA damage on miscarriage rates was performed. Searches were conducted on MEDLINE, EMBASE and the Cochrane Library without any language restrictions from database inception to January 2012.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We used the terms 'DNA damage' or 'DNA fragmentation' combined with 'miscarriage', 'abortion' or 'pregnancy' to generate a set of relevant citations. Data extraction was performed by two reviewers. Study quality was assessed using the Newcastle-Ottawa Scale. Meta-analysis of relative risks of miscarriage was performed with a random effects model. Subgroup analyses were performed by the type of DNA damage test, whether the sperm examined were prepared or from raw semen and for pregnancies resulting from IVF or ICSI treatment.

MAIN RESULTS AND THE ROLE OF CHANCE

We identified 16 cohort studies (2969 couples), 14 of which were prospective. Eight studies used acridine orange-based assays, six the TUNEL assay and two the COMET assay. Meta-analysis showed a significant increase in miscarriage in patients with high DNA damage compared with those with low DNA damage [risk ratio (RR) = 2.16 (1.54, 3.03), P < 0.00001)]. A subgroup analysis showed that the miscarriage association is strongest for the TUNEL assay (RR = 3.94 (2.45, 6.32), P < 0.00001).

LIMITATIONS, REASONS FOR CAUTION

There is some variation in study characteristics, including the use of different assays and different thresholds for DNA damage and the definition of pregnancy loss.

WIDER IMPLICATIONS OF THE FINDINGS

The use of methods which select sperm without DNA damage for use in assisted conception treatment may reduce the risk of miscarriage. This finding indicates that assays detecting DNA damage could be considered in those suffering from recurrent pregnancy loss. Further research is necessary to study the mechanisms of DNA damage and the potential therapeutic effects of antioxidant therapy.

STUDY FUNDING/COMPETING INTEREST(S)

None.

Sperm DNA integrity assays: diagnostic and prognostic challenges and implications in management of infertility

Sperm is not a simple carrier of paternal genetic information but its role extends clearly beyond fertilization. Integrity of sperm genome is an essential pre-requisite for birth of healthy offspring and evaluation of sperm should entail DNA integrity analysis. DNA integrity analysis is a better diagnostic and prognostic marker of sperm reproductive potential. Conventional semen analysis emphasizes on sperm concentration, viability, motility and morphology and has been proven to be a poor indicator of reproductive potential and pregnancy outcome. To overcome the drawbacks associated with conventional semen analysis more useful fertility tests and molecular biomarkers have been explored. Among the different tests which have evolved for assessing the sperm reproductive potential, tests for sperm DNA quality are most promising. Sperm DNA damage has been closely associated with numerous indicators of reproductive health including fertilization, embryo quality, implantation, spontaneous abortion, congenital malformations and childhood diseases. It therefore has great potential as a prognostic test for both in vitro and in vivo conception. This review presents an updated account of tests that have better diagnostic and prognostic implications in the evaluation of sperm DNA damage. The basic principles, outline of methodology, advantage, disadvantage, clinical significance of each technique and implications of these tests have been discussed. The logistics of each test with respect to available resources and equipment in an andrology laboratory, the feasibility of performing these tests in routine diagnostic workup of infertile men and the opportunities and challenges provided by DNA testing in male fertility determination are also presented.

Is sperm DNA damage associated with IVF embryo quality? A systematic review

PURPOSE

Sperm DNA damage is common amongst infertile men and may adversely impact natural reproduction, IUI-assisted reproduction and to a lesser degree IVF pregnancy. The objective of this study was to examine the influence of sperm DNA damage on embryo quality and/or development at IVF and ICSI.

METHODS

We conducted a systematic review of studies that evaluated sperm DNA damage and embryo development and/or quality after IVF and/or ICSI.

RESULTS

We identified 28 studies (8 IVF, 12 ICSI and 8 mixed IVF-ICSI studies) that evaluated the relationship between sperm DNA damage and embryo quality. These 28 studies evaluated 3226 treatment cycles (1033 IVF and 873 ICSI, 1320 mixed IVF-ICSI cycles) and demonstrated highly variable characteristics. In 11 of the 28 studies (1/8 IVF, 5/12 ICSI and 5/8 mixed IVF-ICSI studies), sperm DNA damage was associated with poor embryo quality and/or development, whereas the remaining 17 studies showed no relationship between sperm DNA damage and embryo quality and/or development.

CONCLUSIONS

This systematic review indicates that the evaluable studies are heterogeneous and that overall, there is no consistent relationship between sperm DNA damage and embryo quality and/or development. The data also suggest that the influence of sperm DNA damage on embryo quality/development may be more significant in ICSI compared to IVF cycles.

Are sperm chromatin and DNA defects relevant in the clinic?

There has been an increase in the use of sperm DNA and chromatin integrity tests in the evaluation of the infertile man with the hypothesis that these tests may better diagnose infertility and predict reproductive outcomes. This review discusses the etiology of sperm DNA damage, briefly describing the tests of sperm DNA damage, and evaluates the relationship between sperm DNA damage and reproductive outcomes. A systematic review of the literature allows us to conclude that sperm DNA damage is associated with lower natural, intra-uterine insemination (IUI), and in vitro fertilization (IVF) pregnancy rates. Studies to date have not shown a clear association between sperm DNA and chromatin defects and pregnancy outcomes after intra-cytoplasmic sperm injection (ICSI). However, we cannot exclude the possibility that very high levels of DNA damage will impact on ICSI outcomes. In couples undergoing IVF or ICSI, there is evidence to show that sperm DNA damage is associated with an increased risk of pregnancy loss. A limitation of this systematic review and meta-analysis is that it does not address the heterogeneity of the individual study characteristics. Although the clinical utility of tests of sperm DNA damage remains to be firmly established, the data suggest that there is clinical value in testing couples prior to assisted reproductive technologies (ARTs IUI, IVF, and ICSI) and in those couples with recurrent miscarriages. Additional, well-designed prospective studies are needed before testing becomes a routine part of patient care.

Sperm DNA damage in male infertility: etiologies, assays, and outcomes

Male factor infertility is the sole cause of infertility in approximately 20% of infertile couples, with an additional 30% to 40% secondary to both male and female factors. Current means of evaluation of male factor infertility remains routine semen analysis including seminal volume, pH, sperm concentration, motility, and morphology. However, approximately 15% of patients with male factor infertility have a normal semen analysis and a definitive diagnosis of male infertility often cannot be made as a result of routine semen analysis. Attention has focused on the role of sperm nuclear DNA integrity in male factor infertility. Here we review the structure of human sperm chromatin, the etiology and mechanisms of sperm DNA damage, current tests available to assess sperm DNA integrity, and effect of sperm DNA integrity on reproductive outcomes.

[Assessing sperm DNA damage]

Infertility affects almost 20% of couples in reproductive age and the male factor being responsible of 50% of this infertility. Among the classic parameters that determine a good seminal quality such as sperm motility, sperm morphology or the quality of the of acrosomes and/or sperm membranes, the integrity of the DNA molecule is crucial to carry out a successful fertilization. Nevertheless, the study of this parameter has not been straightforward approached. This fact has shunned its incorporation, as a routine technique, within a standard seminogram. The aim of the present review is to summarize and update those technologies that are considered more successful to study sperm DNA fragmentation with special emphasis to: 1) the levels of technological complexity and the possibility of its use in laboratories of andrology, according with the equipment and the resources available, and 2) the effects and possible implications of high level of sperm DNA fragmentation for fecundation, embryo development and fertility.

Do sperm DNA integrity tests predict pregnancy with in vitro fertilization?

OBJECTIVE

To evaluate the predictive value of sperm DNA integrity tests for pregnancy from in vitro fertilization treatment.

DESIGN

Systematic review and meta-analysis.

SETTING

Studies from infertility centers.

PATIENT(S)

Infertile couples undergoing in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) treatment.

INTERVENTION(S)

Sperm DNA integrity tests before IVF and ICSI cycles.

MAIN OUTCOME MEASURE(S)

Diagnostic test properties for sperm DNA integrity tests with reference to pregnancy after IVF or ICSI treatment.

RESULT(S)

Among 22 relevant studies, 2 x 2 tables were constructed from 13 studies involving 18 estimates of the diagnostic test properties of sperm DNA integrity tests in 2162 cycles of treatment. The sum of sensitivity and specificity ranged from 0.83 to 1.59. In six of 18 estimates abnormal DNA integrity was associated with a higher than expected pregnancy rate. The summary diagnostic odds ratio was 1.44 (95% CI, 1.03, 2.03), but the summary likelihood ratios (LR) were not predictive of pregnancy outcome (LR+ = 1.23; 95% CI, 0.98, 1.54; LR- = 0.81; 95% CI, 0.67, 0.98). Neither sperm chromatin structure assay nor terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling assay tests were more predictive of pregnancy outcome after IVF/ICSI, and DNA integrity testing was not more predictive for IVF than ICSI.

CONCLUSION(S)

The small but statistically significant association between sperm DNA integrity test results and pregnancy in IVF and ICSI cycles is not strong enough to provide a clinical indication for routine use of these tests in infertility evaluation of men. It is possible that yet to be determined subgroups of infertile couples may benefit from sperm DNA integrity testing.

Significant decrease in sperm deoxyribonucleic acid fragmentation after varicocelectomy

OBJECTIVE

To measure sperm DNA integrity values before and after varicocelectomy in patients with elevated preoperative levels of sperm DNA fragmentation.

DESIGN

Retrospective.

SETTING

Private urology clinic.

PATIENT(S)

Eleven patients with grade 1, 2, or 3 varicocele.

INTERVENTION(S)

Varicocelectomy.

MAIN OUTCOME MEASURE(S)

Sperm DNA fragmentation values were assessed before and after varicocelectomy.

RESULTS(S)

Ninety percent of the patients showed a significant decrease in sperm DNA fragmentation levels.

CONCLUSIONS(S)

Although this study was small, 10 of the 11 patients with varicocele showed a significant decrease in sperm DNA fragmentation after varicocele repair. Elevated sperm DNA fragmentation has been shown to have a significant negative effect on pregnancy outcome with use of in vivo, IUI, routine IVF, and to a lesser extent intracytoplasmic sperm injection fertilization; therefore pregnancy outcome may improve after varicocelectomy.

DNA damage of human spermatozoa in assisted reproduction: origins, diagnosis, impacts and safety

Sperm DNA contributes half the offspring's genomic material and abnormal DNA can lead to derangements in the reproductive process. Normal sperm genetic material is required for successful fertilization, as well as for further embryo and fetal development that will result in a healthy child. Thus, the damage to sperm DNA is critical in assisted reproductive techniques which are increasingly used to treat infertile couples. There has been improving data about the effects of human sperm DNA damage or fragmentation. As well, increasing knowledge concerning the effects of DNA damage on embryo and fetal development has been attained. This review aims to summarize the present knowledge on the impact of human sperm cell DNA damage on male infertility and outcome in the context of safety.

Sperm deoxyribonucleic acid fragmentation as a prognostic indicator of assisted reproductive technology outcome

OBJECTIVE

To examine sperm DNA fragmentation in semen used for assisted reproduction procedures to establish this factor's prognostic role in fertilization rate, embryo development, pregnancy rate, and outcome.

DESIGN

Prospective study.

SETTING

Department of Medicine and Biology of Reproduction of the Edouard Herriot Hospital in Lyon, France.

PATIENT(S)

322 couples, divided into 88 cycles of in vitro fertilization (IVF) or 234 cycles of intracytoplasmic sperm injection (ICSI).

INTERVENTION(S)

Sperm DNA fragmentation was detected in sperm obtained 2 to 5 months before the ART procedure.

MAIN OUTCOME MEASURE(S)

Sperm DNA fragmentation was measured with the terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP nick-end labeling (TUNEL) technique.

RESULT(S)

There was a negative statistical correlation between the rate of fragmentation and the semen characteristics. A statistically significant negative relationship was found for sperm DNA fragmentation and fertilization when ICSI and IVF were compared. With ICSI, a statistically significant negative relationship was found between fertilization rate and percentage of sperm DNA fragmentation (DNA fragmentation index, or DFI). The risk of nontransfer due to blocked embryo development increased when the DFI exceeded 15% (18.2% for ICSI vs 4.2% for IVF) with an odds ratio of 5.05. The miscarriage risk increased fourfold when the DFI exceeded 15% (37.5% for ICSI vs 8.8% for IVF).

CONCLUSION(S)

Sperm DNA fragmentation measured 2 to 5 months before the assisted reproduction procedure was a prognostic indicator of the fertilization, pregnancy, and miscarriage rates and the pregnancy outcome.

Sperm DNA integrity assessment in prediction of assisted reproduction technology outcome

BACKGROUND

The sperm chromatin structure assay (SCSA) has been suggested as a predictor of fertility in vivo as well as in vitro. The available data however, have been based on limited numbers of treatments. We aimed to define the clinical role of SCSA in assisted reproduction.

METHODS

A total of 998 cycles [387 intrauterine insemination (IUI), 388 IVF and 223 ICSI] from 637 couples were included. SCSA results were expressed as DNA fragmentation index (DFI) and high DNA stainable (HDS) cell fractions. Outcome parameters were biochemical pregnancy (BP), clinical pregnancy (CP) and delivery (D).

RESULTS

For IUI, the odds ratios (ORs) for BP, CP and D were significantly lower for couples with DFI >30% as compared with those with DFI < or =30%. No statistical difference between the outcomes of ICSI versus IVF in the group with DFI < or =30% was seen. In the DFI >30% group, the results of ICSI were significantly better than those of IVF.

CONCLUSIONS

DFI can be used as an independent predictor of fertility in couples undergoing IUI. As a result, we propose that all infertile men should be tested with SCSA as a supplement to the standard semen analysis. When DFI exceeds 30%, ICSI should be the method of choice.